Thursday, May 9, 2013

4. The Meredith Kercher Case - Back to the Drawing Board (Part Four)

The evidence gets really confusing....


I started out this new series because the Italian Court of Cassation recently quashed the Appeal Court's acquittal of both Amanda Knox and Raffaele Sollecito.

In Parts One through Three, I talked about the Appeal Court's decisions pertaining to the break-in and the DNA evidence (the evidence with regard to the "double-DNA" knife and the bra clasp).

In this part, I'll start to wrap things up by discussing the most interesting other aspects of the Appeal Court's ruling. I will focus on the footprint on the bathroom mat - which inevitably leads one to evaluate whether or not a clean-up operation took place -  and the traces left by  Luminol found in various places in the apartment at the Via della Pergola.  

The print on the mat and the clean-up

In the smaller of the two bathrooms in the upper floor of the house at the Via della Pergola (the bathroom used by Kercher and Amanda Knox, just next to Kercher's bedroom), a mat was found on which the imprint of someone's bare right foot was found. The print was made due to the fact that the foot has been bloodied; the blood was Kercher's.

The original court, after having heard the expert testimony from both the prosecution and the defence, decided that the footprint matched the right foot of Sollecito.

The Appeal Court rejects this, coming to the conclusion that the print is "of no evidentiary value against defendant Sollecito". In fact, the court states: "It cannot (...) be ruled out that Guede (...) experienced the loss of his right shoe in the course of the violent aggressive manoeuvres to which he subjected Kercher, thus resulting in the soiling of his foot with blood, which he took it upon himself to wash in the small bathroom situated immediately to the left of the door to Meredith’s bedroom. Otherwise, his right shoe should also have left some kind of bloody trace along the corridor as he exited; he likely went through it, however, with his right foot bare, even if cleaned of blood by this point."

Now before addressing the forensic evidence regarding possible matches of the footprint, there is another issue to bear in mind. Is the fact that print existed in the first place of any relevance for the question as to whether more than one person was involved in the murder?

Well, if we consider the Appeal Court's reasoning, as quoted above, one might assume that something along the following lines must have happened: 
  •  sometime during or preceding the attack on Meredith, Guede loses his right shoe;
  • Guede kills Kercher, doing so in such a manner as to inevitably leave considerable amounts of her blood in her room and, no doubt, on his person. He also leaves evidence of his presence in her room (there is, for example, the imprint of his bloodied hand on a pillow). He then goes to the bathroom to wash his bare foot;
  • he then cleans up, thereby forgetting or not noticing the single footprint on the bathmat (and, indeed, the hand on the pillow), and possibly puts his shoe back on (or perhaps, as the Appeal Court assumes, he does not);
  • and he then departs, leaving, however, a discernible trail of shoe prints from his left shoe.

If one accepts such a sequence of events, a clear problem arises. After all, if you wish to believe that the same person (i.e. Guede) could have left both the footprint on the mat and the shoe prints, you would have to accept that that person would have had to be, at one and the same time, cautious enough to have cleaned up after the attack (and even, at least to a certain extent, to have "rearranged" the crime scene), but careless enough to ultimately walk out of the apartment with a clearly bloodied shoe (and the mark of his hand on a pillow). He would have had to spend considerable time and attention to trying removing his presence in some ways, whilst at the same time not caring at all whether his presence was discernible by other means. (I should perhaps at this point bring into recollection that the shoe prints leading from Kercher's room to the exit were visible to the naked eye; these were not traces only discernible by the use of Luminol.)

In other words, it seems fairly clear that the two sets of actions could not have been taken by one single person. They are, simply put, contradictory in nature. To a certain extent, the Appeal Court itself inadvertently strengthens this contradiction, when it assumes that Guede left the apartment wearing only his left shoe, with his right foot still bare. That, certainly, is the action of someone who wants to leave as quickly as possible, and not the action of someone who has decided, instead, to stay for a while and remove as much evidence as possible. Besides, it seems rather absurd to suppose that Guede would have cleaned up the place whilst wearing just one shoe.

The Appeal Court however, recognises the problem, and deals with it in a way that is quite crucial not just to the issue of the footprint on the mat but also to the issue of the traces revealed by Luminol (which I'll discuss later). It does so by assuming there was no clean-up.

I must admit that when I first realised this, I was momentarily at a loss for words. That the apartment had, at least partially, been cleaned after the attack had been, for me, a given (as it had been for the original court, which stated that "a cleaning activity was certainly carried out".)

The Appeal Court's reasoning on this cannot be found in its deliberations concerning the footprint; it is only when one arrives at the court's reasoning with regard to the traces left by Luminol that this aspect of the ruling becomes clear. There, the court expressly rejects the idea that any clean-up took place: "the occurrence of a clean-up is negated by the sheer number of traces found in the house", the court states.

I must admit I have no true understanding of how the Appeal Court might find this to be the case. If Kercher was murdered in the way she was murdered - that is, stabbed repeatedly with one or two knives - she would have lost a considerable amount of blood. Whoever attacked her must gotten that blood on them; the blood must have gotten on their (bare or shod) feet. Of course some sort of clean-up took place, and this follows from the simple fact that the very next day, various people (not just Knox and Sollecito, but also Romanelli, a friend of hers and both their boyfriends, along with two officers from the Postal Police) all entered the apartment and none of them, at that point in time, realised that they were walking into the scene of a violent murder. It follows from Knox's own testimony: she states she had earlier taken a shower and not realised anything was actually wrong; she noticed on or two little blood stains but assumed someone had had her period. And, certainly, it follows from the single footprint on the bath mat in the small bathroom, with the absence of any other prints leading from Kercher's room to the bathroom and the mat.  

In short, if the fact that some sort of clean-up had taken place seemed, to me, a given, that is because it is. I don't see how you can get around that at all; any other idea would appear to be totally illogical. Nevertheless, that is the assumption of the Appeal Court, and because of this, I feel that that court's reasoning is seriously suspect.

Now, I have already said that, if you do assume a clean-up took place, this also implies that the Appeal Court's reasoning with regard to the footprint on the bath mat becomes clearly illogical.


It is only when the above issues has been addressed that the next question arises, which is whether or not the forensic evidence shows if the print matches Sollecito's foot. As to that question, I will try to be brief. The reason is very simple: I'm basically at a loss.

You see, the experts of the police came to the conclusion that the print was compatible with Sollecito's foot, but incompatible with Guede's.  However, the expert hired by Sollecito, professor Vinci, disagreed: he stated that the print could, indeed, have been left by Guede. To substantiate this, Vinci made one very important assumption, which is that the print of the foot's big toe is actually not a print of just that toe, but also a print of the next (or second) toe. The print is therefore merged; it's two toes. This is important because it turns out that Sollecito's big toe is actually much bigger than Guede's. In other words, to explain the size of the print when it comes to the big toe (to explain that the print could nevertheless be Guede's), the defence had to assume that the print was two toes.

Now the original court rejected Vinci's claim, using a rather simple argument: it stated that the print was clearly homogenous. If it had been the merged print of not one but two toes, there would have had to have been some incongruity, some "interruption of continuity" (as that court states) in the print. However, there is none, the court alleges.

The Appeal Court , however, states the opposite, where it confirms that "examining the black and white images [in professor Vinci's report], one remains convinced of the validity of his belief."

And that's basically it. In other words, the original court looks at the print and decides it's Sollecito's foot, whilst the Appeal Court looks at the print (the photos in Vinci's report) and decides that it could well be Guede's.

As a result, I have no clear idea of which court's opinion is the more valid. I can only turn to a few rather vague ideas and notions. Whilst these, by and large, would seem to indicate that, yes, it's rather more likely that we're talking about Sollecito's print than Guede's, that's just not enough.  

As to what the Court of Cassation made of this, once again I don't know. From a strict legal point of view, I would have to assume that that court might well have had to accept the Appeal Court's reasoning, since it doesn't seem to be overtly illogical or insufficiently substantiated. 

Please remember though, that we are only talking about possibilities (or probabilities). Neither the original court or the Appeal Court rules out in any absolute sense that the print could have been made by either Sollecito's or Guede's foot. As a result, the remarks I made earlier - regarding the relevance of the print when it comes to the question of a "lone wolf" criminal - remain quite intact, as do my comments regarding the clean-up. And these, to my mind, are the central issues.


Sollecito's foot
Guede's foot


Click on either image for a larger picture.
As to the footprint on the mat, here are the measured sizes: Big toe height = 39. Big toe width = 30. 
Metatarsus height = 50. Metatarsus width = 99. 
(The photos are from the prosecution's report.)


The Luminol prints

As the Appeal Court correctly states, during the second inspection of the house at the Via della Pergola, on the 18th of December, 2007, Luminol was applied to the floor of the corridor, to the kitchen/living-room, to the bedrooms of Knox and Filomena Romanelli, and, finally, to the larger bathroom.

Now, Luminol is a substance that can detect the (invisible) existence of blood, but it reacts equally to other substances, like fruit juice or bleach.

The use of Luminol revealed various traces (I believe there were six traces in all). These traces were further examined; that is, they were, firstly, examined as to whether it could established that they were left by blood. Secondly, DNA samples were taken and tested.  

As for the blood sample testing: all the results came up negative. It could not, in other words, be established that the traces were blood traces.

As for the DNA testing: two traces were found to contain the mixed DNA of both Knox and Kercher. One of these traces had been taken in Romanelli's room; the other had been taken in the hallway. The other four traces did not contain mixed samples, but they did contain the DNA of just Knox.

The original court, in considering this outcome, came to the conclusion that in the case of the two mixed samples, a reasonable supposition is that these traces consisted of the blood of Kercher, mixed with the DNA of Knox. In doing so, that court takes into consideration that whilst the testing done did not establish the existence of blood, there was no sufficient reason to exclude the possibility that they had, nevertheless, been blood samples.

The Appeal Court disagreed, stating the following: "First and foremost, the certain, true fact is that the generic blood test gave a negative result. According to the [first] Court this happened because of the scarcity of the available biological material, but the consultant for the defense, (...) specified (....) that the (...) test is very sensitive, so much as to give a positive result even with only five red blood cells present. Dr. Stefanoni herself, moreover, clarified (...) that, while a positive test result could be deceptive due to reactivity of the chemical with other substances, a negative result gives certainty that no blood is present."

The first thing that should be noted here is that the Appeal Court has muddled its facts. Dr Stefanoni (who is attached to the Scientific Police and therefore the prosecution) was, at the time, clearly talking about the results from the use of Luminol, not the results from specific and subsequent blood tests. And her remarks seem correct: a negative Luminol test will no doubt be conclusive (i.e. if the Luminol does not cause a reaction, well then, no blood, or any other substance that reacts to Luminol, will be present). This, however, clearly does not apply to the six traces in question, since all these traces led to positive Luminol results; there was a reaction. 

What we are left with is the true statement that the specific blood test lead to a negative result. Here, however, the same applies as when examining the "double-DNA" knife and the bra clasp: the fact that it could not be established that Kercher's DNA sample on the knife was left by blood, or Sollecito's sample on the clasp was left by his handling of the clasp, does not in itself rule out either possibility.  It simply means that the answer to that question must be sought elsewhere, by different means.

The means by which the original court reaches its answer is relatively straightforward. We have, that court considers, the positive Luminol samples. Then we have, in two cases, further DNA samples that were mixed (they contained both the DNA of Knox and Kercher).  What is the most reasonable explanation for this? Well, the original court states, it's surely that Knox, in her bare feet - feet still bloodied with Kercher's blood - left these traces.

To which it can be added that one of the traces (the one in Romanelli's room) does not seem attributable to a bare foot (it is simply amorphous). The second trace, however (the one found in the corridor), does seem to have been left by a foot (indeed, it seems to have been left by Knox's foot).*

And to which it can further be added that any other explanation seems much more improbable. In particular, the notion that the two mixed traces could just be evidence of the fact that both Knox and Kercher happened to live in the same apartment seems unlikely. After all, such an idea would necessitate that , at two very specific places and at more or less the same time, Knox and Kercher both left their DNA traces, and you would further have to assume that, again at the same place and at more or less the same time, some innocuous substance with which Luminol reacts (such as fruit juice or bleach) was used. If you assume that substance to have been incidental, such as, say, spilled fruit, common sense dictates that the odds of this having happened become very high indeed; if, alternatively, you presume a much more generic substance caused the reaction, such as bleach, the opposite apples; it becomes almost impossible to understand why only two traces were found.

In other words, the original court reached its decision on the basis of a fairly logical set of thoughts, and one that I, at least find compelling.

It is interesting to note that the Appeal Court seems to have all sorts of difficulties in trying to reach an opposing view. The court starts by assuming the Luminol traces could indeed have been caused by bleach. After all, why not? There were four young women living together in the apartment, who must have had friends coming over regularly; bleach must have been used often. In doing this, however, the Appeal Court is already starting to miss the crux of the matter; after all, it is not just the positive Luminol test that is indicative, it is the combination of that test and the DNA sampling, and the fact that so few traces were found, which is important.

Perhaps because of this, the Appeal Court goes on to make two further remarks. Firstly, it states the following: "The limited number of footprints detected can be explained by treading at different times and by the use of bleach on points specifically dirty.  After all, doubts similar to those raised in the ruling could be brought up even supposing that the traces are of blood: why only in those few points, moreover not consecutive and instead spread in various rooms?"

This quotation is, it must be said, truly odd. If the traces were a reaction to bleach, surely there must have been a lot more of them. So the Appeal Court is trying to explain why there were, in fact, so few. And in doing so, it immediately ties this issue to another one altogether, which is the question of why only two mixed DNA samples were found.

Well, that question has already been answered by the original court, and that court's answer was simple: a clean-up operation had taken place. So one would expect the Appeal Court to concur, this, after all, explained the conundrum the Appeal Court itself had just made obvious.

What, however, does the Appeal Court do? It immediately and rather astonishingly rejects the idea of a clean up. The second remark it makes is: "the occurrence of a clean-up is negated by the sheer number of traces found in the house".

It is at this point that one must seriously consider that the Appeal Court has more or less lost the ability to think straight. The court starts its arguments by asking itself why there are so few footprints. It links this to the fact that, well, there are only two mixed DNA traces, too. It then offers the answer to the question of how this can be the case: there must have been a clean-up. It then rejects that notion. And how does it do this? By pointing to "the sheer number" of traces.  I think the only correct response to all this would be: "Eh?"

Having said this, however, I must point out that the Appeal Court, after this momentary lapse of reason, comes back quite strongly. It finishes its arguments on the traces left by Luminol with a simple and possibly adequate remark, stating that the DNA in the mixed samples was once more so small that LCN testing was required. And just like the testing done with the knife, serious questions can be raised as to the reliability of the results procured. Once more, the question arises if the tests conducted by the Scientific Police were adequate since, once more (as the Appeal Court states), just a single test was carried out (and, as far as I know, no new testing - done, perhaps, on the basis of methods "still in development" - can be done). 

So, how will the Court of Cassation have thought about all this? Well, at the very least I would assume that it could not have overly pleased with the Appeal Court's considerations; these are, in many ways, clearly illogical in very substantive ways.  Of course some sort of clean up seems to have taken place; the Appeal Court's negation of this makes very little sense at all. So of course there is the very real question as to whether Guede could and would have engaged in this clean up and if not, if that fact alone does not clearly point to the guilt of Knox and Sollecito. And of course the traces left by Luminol should be taken seriously in this regard. And yet, there remains the unclear answer to the question of whether or not the footprint on the mat should or should not be attributed to Sollecito. And there remains the question of whether the results of the LCN testing on the mixed samples can or cannot be considered reliable. And I am uncertain as to how the Court of Cassation has answered either of these questions. 

* This paragraph was edited on the basis of the comments you can read below. Originally, I had stated that both prints were attributable to bare feet, thereby following the Appeal Court's statements. The Appeal Court seems to have been wrong, though.


Chris Halkides said...

There is at least one obvious error in this essay: The presence of DNA is not a confirmatory test for the existence of blood. I know of no forensic textbook or other source that would claim otherwise. But your essay brings to mind the question of why Meredith's DNA did not show up in each and every luminol-positive location.

With respect to the luminol-positive/TMB-negative/DNA-negative areas, I asked the authors of a 2009 review article on the forensics of body fluid identification for their interpretation. Drs. Virkler and Lednev wrote, “So, there was either no blood and the luminol was wrong, or there was blood and the TMB had interference and the luminol damaged the DNA. We think it is more likely that there was no blood, and that the luminol was reacting with something else, possibly plant matter from the bottom of the shoes causing the footprints (the intensity of the luminol reaction might give some more insight). The prosecution should have used much more convincing evidence to prove the presence of blood.”

Alex van den Bergh said...

Dear Chris,

If I did indeed state that the presence of DNA confirmed the existence of blood, you're right. It doesn't. I quickly reread the post, but I don't see the error, though.

Chris Halkides said...

Dear Alex,

It may be that I misinterpreted your statement, "it is not just the positive Luminol test that is indicative, it is the combination of that test and the DNA sampling, and the fact that so few traces were found, which is important." Yet, the problems with the luminol results are manifold. One TMB gave negative results. My recollection is that Stefanoni was indeed speaking of TMB in 2008, and this quote might also be in the appeal documents (but I could easily be mistaken). Two, no confirmatory tests were done. The sensitivity of one common confirmatory test is such that it can detect blood that has been diluted about one millionfold, which is similar to published values for luminol. Beyond fruit juice and bleach, rust and certain other metal ions can produce a false positive in the luminol test; therefore, a confirmatory test is required before the one can conclude that blood is present.

Three, no reference footprints of Amanda's other flatmates were taken. Four, the luminol was overapplied, leading to puddling and therefore to measurements that were more likely to be in error. Five, the luminol print in Amanda's own room (Rep. 180) does not match her reference print, especially at the second toe. If that is not Amanda's footprint, then who made it and when? It would presumably be another female, and it was probably made before 1 November. If that luminol print is not blood, can we conclude that the other prints are made in blood?

Alex van den Bergh said...

Hi Chris,

Thanks for posting.

To be honest, I can't immediately answer all the points you raise :)

But don't worry, I'll be happy to look at them as soon as possible.

For what it's worth, though, I do re-iterate that I won't ever be looking at evidence that is not part of either courts' verdicts. Mine is a legal approach, and whilst I certainly appreciate that all sorts of people feel that this case should be decided on issues that are not mentioned in the verdicts given, that is simply not an area I will ever enter. If I did, I'd simply become one of the "pro" or "contra" crowd.

I'll try to get back to your issues tomorrow.

Alex van den Bergh said...

Dear Chris,

I've re-read your post. I must admit I don't quite see the point you're trying to make.

The original court found that the most reasonable explanation for the two mixed samples (the samples containing the DNA of both Kercher and Knox) was that Knox, in her bare feet - feet still slightly bloodied with Kercher's blood - left the traces.

It is certainly true that no test positively identified the presence of blood. That being the case, I fail to see the importance of any "confirmatory testing" being done, unless of course you feel that such a new test might somehow have turned things round and might actually have established that blood was present (a view you clearly do not hold). I also fail to see what importance can be attached to the negative traces. They are what they are - negative traces - and no more than that. That Luminol was "over applied" as you state, is news to me; again I fail to see what should be inferred from this when it comes to the two mixed samples. In any case, the "over applying" played no part in either courts' deliberations.

That, finally, there was a footprint in Knox's room that did not match her feet is not something I can confirm. I might be wrong, but as far as I know neither the original court nor the Appeal Court has mentioned this. Are you perhaps confused with the footprint found in the small bathroom? In any case, from the trace found in Knox's room a DNA sample was taken and it was established that the DNA was Knox's (and not anyone else's).

All in all, I cannot see how "the problems with the Luminol results are manifold". The only "problem" is what inference must reasonably be made from the two mixed DNA samples. That's not really a problem, though, just a matter of good judgement.

Now on to dr. Stefanoni. I must admit I was quite surprised to read, in the Appeal Court's verdict, that Stefanoni herself has said that a negative blood test "gives certainty that no blood is present" (to use the Appeal Court's words). It is only when you read the court's remarks for a second or third time that you realise she is talking, not about a blood test, but a Luminol test.

In any case, just to be sure, I went back to the original court's verdict. It extensively deals with dr. Stefanoni's various remarks in the case, and at no point does it mention that Stefanoni might actually believe that a negative blood test is conclusive in establishing the non-presence of blood. In fact, quite the opposite is true.

Here, for example, is what (in the words of the original court) Stefanoni said when it comes to the negative blood test performed on the double-DNA knife:

"Dr. Stefanoni, [when] questioned on this specific aspect, noted that since any DNA that might be present on the trace in question was certainly of a very small quantity, a minimal quantity was used to determine whether the trace was of a haematological nature or not: consequently the outcome of the test, [which was] negative for blood, did not necessarily signify the non-haematological nature of the trace, as it might have been derived from too small a quantity of material to have allowed a positive result, even if that substance had been blood."

And, just to put your mind at rest, here's what the defence expert, dr. Gino, said (again, I'm quoting the original verdict):

"Dr. Sarah Gino (...) underlined that the (...) reports which had been made available had shown that a generic diagnosis for blood had been performed and had given a negative result, and therefore it could not be said with certainty that blood was present in the material revealed by Luminol."

That amounts to basically the same thing. There seems to be, in other words, little controversy here between prosecution and defence. A negative blood test does not conclusively establish that no blood was present.

Chris Halkides said...

Dear Alex,

Now it is my turn to be puzzled. Are you saying that each and every luminol-positive area definitely is blood? I will proceed assuming that the answer is yes, but I will have to break my thoughts up into more than one comment.

From p. 258 of the English translation of the Massei report, “She [Sarah Gino] added that, in her own experience, analyses performed with TMB on traces revealed by Luminol give about even results: 50% negative, 50% positive, [276]” From the English translation of the Hellmann report, “Professor Tagliabracci, specified, without being refuted (hearing of July 18 2009, p. 174), that the tetramethylbenzedine (TMB) test is very sensitive, so much as to give a positive result even with only five red blood cells present. Dr. Stefanoni herself, moreover, clarified (preliminary hearing of October 4 2008) that, while a positive test result could be deceptive due to reactivity of the chemical [evidenziatore] with other substances, a negative result gives certainty that no blood is present.” It is my understanding that Stefanoni was speaking of the TMB test. Do you disagree?

With respect to the overapplication of luminol, my source is Colonel Garofano in the book “Darkness Descending,” p. 376. The reason why dilation of the prints is important is that it weakens one’s ability to attribute them to an individual. Another problem with attributing some of them to Amanda is that no reference prints were taken from Laura, Filomena, or Meredith, to the best of my ability to ascertain. Page 17 of the first Rinaldi report (available at InjusticeAnywhere) has a photograph of the luminol-positive print from Amanda’s room, and her reference footprint is on p. 44. The two prints look dissimilar to me. With respect to finding Amanda’s DNA within the luminol-positive area, the connection between the luminol-positive material and her DNA could have been made stronger if the prosecution had used substrate controls: if test areas nearby the stain of interest did not have Amanda’s DNA, then there would some reason to relate the two.

Alex van den Bergh said...

Dear Chris,

No. I am not saying that "each and every luminol-positive area definitely is blood". Wherever did you get that idea from?

Chris Halkides said...

Dear Alex, You wrote, "What is the most reasonable explanation for this? Well, the original court states, it's surely that Knox, in her bare feet - feet still bloodied with Kercher's blood - left these traces." What did you mean, if not that the luminol positive areas in this case were all blood?

Alex van den Bergh said...

Dear Chris,

I should, perhaps elaborate slightly.

You wrote: "It is my understanding that Stefanoni was speaking of the TMB test. Do you disagree?"

I'm not entirely certain what you mean by "TMB test". If, however, you mean the negative blood test (and not the spraying with Luminol), well then yes, I certainly disagree. I've already explained why.

It's very simple, really. If you spray with Luminol and get no reaction, no reacting substance (such as blood) is present. But if you do a blood test and it's negative, there is no certainty there is no blood.

Alex van den Bergh said...

Dear Chris,

Our earlier posts sort of criss-crossed.

In reply to your last post: I was talking about the two Luminol traces where mixed DNA was found.

I was not talking about all the positive Luminol traces (with or without DNA having been found).

Chris Halkides said...

I believe that the generic test is the same as the tetramethylbenzidene (TMB) test. What is your explanation for why it is negative?

Alex van den Bergh said...

Hi Chris,

Do you know, it might be worthwhile to attempt to clarify things a bit here.

In this part of my series, I addressed, among other things, the issue of the Luminol prints. In your first remark, you assumed that I had stated that the presence of DNA confirmed the existence of blood. That was not, however, a statement I made, and you have been so kind as to accept this.

You then went on to point to "the manifold problems" of the Luminol results. Personally, I don't believe there are "manifold" problems, and I've explained why.

You also pointed to dr. Stefanoni's alleged comment, as quoted by the Appeal Court, that a negative blood test firmly establishes that no blood is present.

And that's basically where we are now. We're talking about whether Stefanoni did or did not state that a negative blood test is conclusive.

Now, I don't believe that Stefanoni actually said what the Appeal Courts thinks she said, and again I have pointed out why, using not just Stefanoni's comments during the original trial, but also the comments of the defence consultant, dr. Gino. In other words, I feel that the Appeal Court has muddled its facts.

If you nevertheless feel that the Appeal Court has quoted Stefanoni correctly, please let me know. In that case, I'd obviously be happy to reconsider the wording of my article. For that to happen, though, a simple question must be asked: can you provide me with a verifiable quote from Stefanoni where she does indeed state that the negative blood tests she conducted firmly establish that no blood was present?

In the end, of course, the question is not what I personally believe; the question is whether the Appeal Court made an error in misrepresenting dr. Stefanoni's comments.

(P.S. My regards to Wilmington. I used to live in Raleigh; my dad was studying at Chapel Hill)



Alex van den Bergh said...


Would you like to respond to my comment?

Chris Halkides said...

Dear Alex,

I was hoping that you would respond to the quotations in my comment from 30 May at 7:57, especially Sarah Gino's observation. I was also hoping that you would clarify what you meant when you wrote, "it is not just the positive Luminol test that is indicative, it is the combination of that test and the DNA sampling, and the fact that so few traces were found, which is important." You have said what you did not mean, but that is not the same thing as saying what you did mean.

Have you had a chance to look at Rinaldi's report? That is where one can find a photo of Rep. 180, as I mentioned previously. This is the luminol print from Amanda's room. I have no idea what you mean by the footprint in the small bathroom. I am not aware of any luminol findings from the small bathroom.

With respect to the attribution of the luminol positive prints in the hallway, my opinion is that the overapplication of luminol noted by Colonel Garofano (the pooling of liquid can be seen in some photos) combined with the lack of reference prints from any woman besides Ms. Knox makes attributing a footprint to her extremely questionable at best.

Now on to tetramethylbenzidine (TMB). It is common practice to follow up a fluorescent experiment with a colorimetric experiment when detecting blood, as I documented at my blog as as noted by Sarah Gino. If the only reason that TMB would give a negative result after a positive result from luminol were that luminol has (somewhat) higher sensitivity, then there would be absolutely no reason for this practice (again there is an extensive discussion of this point at my blog).

One more clarification may be needed. There are three areas of mixed DNA from Amanda and Meredith, other than in the small bathroom. One is a shoe print in the hallway (Rep. 183), and two are amorphous blobs in Filomena's room (Reps. 176 and 177), one of which may be too weak to ascribe to Amanda. There has been disagreement in on-line discussions about whether or not the print in the hallway with mixed DNA was a shoe print or a footprint, but I believe that it is the former, and it may be that the image on p. 19 in the Rinaldi report is Rep. 183. Thus, nothing in either the hallway or Filomena's room that has mixed DNA actually has the clear outline of a woman's foot.

I will try to come back to the rest of your points when I can.

Alex van den Bergh said...

Hi Chris,

I'm sure all the arguments you raise are, in various ways, interesting.

But in the end, we already have two verdicts and are awaiting the ruling to be given by the Court of Cassation. The point of my series is to attempt to figure out where the Appeal Court (in the eyes of the Court of Cassation) erred.

Now, one of those errors (a rather mild one, to be honest) seems to be that the Appeal Court has substantiated its decision that the two mixed DNA samples obtained after the use of Luminol did not contain blood by pointing to the fact that dr. Stefanoni has remarked that a negative blood test "gives certainty that no blood is present".

If dr. Stefanoni actually said that, well then, my criticism of the Appeal Court could well be wrong. If, however, dr. Stefanoni did not say anything of the sort, my criticism stands.

So that's why I asked you whether you might have some sort of verifiable quote from her which would prove the court's right. If you don't, fine - we can then move forward with any other argument you wish.

Do remember, though, that a lot of the arguments being made by all sides in this matter don't really reflect the reality of the verdicts already given. For example, the discussion with regard to discovery might well be interesting in and of itself, but discovery didn't play a part in the original court's verdict and it didn't play a part in the Appeal Court's verdict. It will not play any part in the ruling by the Court of Cassation, either.

So in terms of the trial and the possible final outcome, that discussion seems rather moot.

Chris Halkides said...

I am still looking into what Ms. Stefanoni said, but I am willing to leave that discussion until new information becomes available. However, I would like to know your reaction to something that Sarah Gino complained about, namely that the negative TMB results were not disclosed to the defense until late into the first trial. Something similar happened in the Lovejoy case in Illinois, and a new trial was granted as a result.

Chris Halkides said...

Dear Alex, You wrote, "After all, such an idea would necessitate that , at two very specific places and at more or less the same time, Knox and Kercher both left their DNA traces, and you would further have to assume that, again at the same place and at more or less the same time, some innocuous substance with which Luminol reacts (such as fruit juice or bleach) was used." I am puzzled by this passage and that which immediately follows it. Neither DNA nor luminol can be dated, and no substrate controls were ever reported. Can you clarify what you mean?

Alex van den Bergh said...

Hi Chris,

Just saw your comments. It's getting very late over here, so please be patient. I'll try and get back to you tomorrow.

Alex van den Bergh said...

Hi Chris,

As promised, a response to your comments.

Firstly - okay. Let's leave dr. Stefanoni aside. I'll simply presume that my assumptions are correct on this and that the Appeal Court's statement was erroneous. If at some point you'd like to come back to this, by all means do.

Now on to the (discovery with regard to) negative blood results. I must be brief here: this is very much the sort of thing that really plays no part in this trial. Neither in the original court's verdict nor in the Appeal Court's judgement is the fact that the negative blood test was not disclosed promptly discussed as an actual issue; it certainly played no part whatsoever in either court's deliberations. It would seem to me that there are far better trees to bark up. (It may well be true that, in the USA, an untimely disclosure is of more importance; however, there are big differences between the criminal systems in the States and in Italy, the biggest being the fact that in a jury system is applied in the US.)

Finally, the comment of mine you have quoted. You're right; neither DNA nor (the traces revealed by) Luminol can be dated precisely. So, in theory, you don't know how the thing plays out temporally. Knox might have left her DNA at time A; Kercher at time B, and the substance which reacted to Luminol might have been left at time C; and all these times might, in theory, not indicate any interconnected activity at all.

However, all three must still have been present when the Luminol test was done. That's an immediate, and important, temporal boundary. For example, if one where to assume (as the Appeal Court does) that the Luminol may well have reacted to bleach, one would then also have to assume that the bleach was applied first and that both Kercher and Meredith then left their DNA. That is itself seems rather unlikely.

Then there's a spatial boundary. In the example just given, one would furthermore have to assume that Kercher and Knox left their DNA not just after the bleach was applied, but also that they did so at exactly the same place. That no longer seems unlikely; it seems very improbable. Not impossible, I dare say, but improbable.

One could, of course, move on to alternatives. One might, for example, presume that the Luminol reacted not to bleach, but to, say, fruit juice. Essentially, though, the same incongruities apply.

It is exactly because of these reasons - (1) you can't precisely date either DNA or Luminol, but (2) you can roughly define a certain timescape by logic, and (3) the DNA was found in exactly the same places - that I said that Knox and Kercher left their DNA traces "at two very specific places and at more or less the same time". Please note the "more or less" qualification.

Please note also that the original court gave no absolute statements on this, either. What it did was state a reasonable supposition, based on all the evidence available. That seems a balanced and rational approach, to me.

Chris Halkides said...

Dear Alex,

I doubt that I will have time for a long response tonight, but I can mention a few things. First, I have no intention of joining you in your presumption about Ms. Stefanoni's comments. Second, I am somewhat surprised that a person who lists his industry as law is not more interested in the two major failures of discovery that happened in the trial of first instance, but so be it. Third, you are ignoring the lack of substrate controls, a point I have raised previously. If the FP had sampled near the luminol-positive blobs in Filomena's room and had not found DNA, they would be on stronger ground in relating the two, but they did not. Fourth, you are drawing an inference from the DNA, yet you state that you are not treating DNA profiles as confirmatory tests for blood. Again I ask you to resolve this paradox.

Chris Halkides said...

One other point about luminol. Besides bleach and plant peroxidase enzymes, a number of things produce false positives. Transition metal ions such as iron (as might be found in rust), copper, and cobalt are one class. A few substances are poorly characterized, according to one paper in the literature.

Alex van den Bergh said...

Hi Chris,

A short response.

Don't worry, I don't expect you to join me when it comes to dr. Stefanoni. I do believe my remarks are accurate, however, and if you cannot correct me on this, I'll clearly keep believing that.

In terms of discovery: well, it's very simple, really. Read the two verdicts, and you'll - ahem - discover that discovery is not an issue. You might disagree with that, but it just isn't. And it most certainly won't feature in the Court of Cassation's ruling either.

Yes, I am drawing an inference from the DNA. More importantly, it's the original court that draws that same inference. I see no paradox here at all, however. From a scientific point of view, the tests that were done did not indicate the presence of blood (the tests were negative). However, from a legal point of view, the inference can still be drawn that the prints were left by the still slightly bloodied feet of Knox. One of the reasons this inference can be drawn is because a negative blood test isn't absolute.

One of the failings of the Appeal Court is that it - erroneously - seems to believe that a negative blood test is, indeed, absolute. Which pushes us back to evaluating dr. Stefanoni's comment, which the Appeal Court (again, erroneously, to my mind) attempted to use to substantiate its position.

Chris Halkides said...

Dear Alex,

I have read the two verdicts, and I am quite baffled by your latest comment about the lack of discovery. Why would the Massei report itself deal with discovery? On the other hand discovery is discussed extensively in Raffaele's 2010 appeal. IMO the supreme court should address this issue as well; what happened in the trial of first instance is contrary to international norms and made the trial itself unfair. That sounds like fair game for the purview of the court. The rest of my reply will have to wait for another time.

Chris Halkides said...

Precisely which print or prints do you mean?

Alex van den Bergh said...

Dear Chris,

I understand your bafflement. It seems to me to be caused by a lack of understanding of the legal process.

You're not the only one: just about everyone discussing this case (both those pro-guilt and those pro-innocence) seem to think that anything they themselves feel important to the case can and somehow will play a part in the way the case is handled further (i.e. in the Court of Cassation's decision, in the decision to be given by the Appeal Court in Florence, and in any further decisions thereafter).

However, that's simply not true.

For example, the Court of Cassation will most definitely not speak a word about discovery at all. Not a word. How can I be so sure of that? Well, because it's not part of the cassation appeal. And since it's not part of the appeal, that issue is quite beyond the court's remit. It's not just that the Court of Cassation wouldn't want to comment on this issue; it's that it can't. It's that simple.

Kaosium said...

Alex, just reading through this perhaps I can clarify something. All these presumptive (in this case luminol & TMB) blood tests rely on natural chemical reactions, if they didn't react every single time they'd be worthless for detecting blood. They're also, in the abstract (potentially) falsifying the possibility of blood, not proving it, the only thing that can do that is a confirmatory test in the lab, like Stefanoni did for the samples not under question.

I'm sure you're right that Cassation will not be addressing discovery issues, but that's not the value of the exploration of the luminol hits to you or I, instead they are the best heuristic of why the entire forensic case is garbage. Let me explain how this works and you'll see what they did and why these luminol hits are worthless.

Remember how I said the presumptive tests are actually a falsifier for blood? That probably surprised you, but scientifically and logically that's what they are. You cannot prove blood with either test, but you can (virtually) eliminate the possibility of it. When you spray luminol on a surface, in this case a floor, you know if it doesn't light up it's not blood, you've falsified that possibility, so you don't bother with those sections anymore. The ones that do light up, might be blood, but since a lot of other things can cause that cool chemiluminescent glow, because they cause the same or a similar reaction, it's best to verify that which is quick and easy to do with a TMB test. If you don't get a (color change) reaction from that, you know it's not (pure) blood either, otherwise you'd get that natural chemical reaction thus again you've falsified that possibility.

If you do get a color change you know you probably have blood so you take the sample back to the lab and do a confirmatory test. A common one involves using anti-bodies that have been harvested from introducing human blood to bunnies, they then take those anti-bodies and expose them to the sample and see if they react, and if they do you know for certain you're dealing with human blood, if they don't you've finally falsified the possibility.

Ain't science cool! But it's tough, isn't it?

In this case they caked that floor with luminol, did the TMB tests and got negatives, never did a confirmatory test but decided to pretend they were real blood anyway because jurors don't know this stuff, one sciency-type drones on about one thing, another one disagrees, real people don't even understand the words they're using, who the hell knows, right? Perhaps you can sympathize!

Kaosium said...

The importance of the disclosure issue is not just some legality, but how it demonstrates their methods in this case. They didn't advance diluted blood in making their case, they pretended those were pure bloody footprints coming out of the murder room. However, then the TMB negatives were revealed, and instead of saying 'we're worthless lying scum and you should punish us,' they decided to pretend they must have been diluted to within the detection range of luminol but below TMB, clever huh? No. not really, that's actually damned unlikely but at any rate it doesn't actually matter that much.

Blood diluted below the TMB (field) threshold of 10,000:1 amounts to the equivalent of 1 ml of blood diluted in 10 liters of water, essentially a drop or so that got in some water or something and got tracked around. That could have been anything, done by any person at any time, any of the girls in the cottage before the murder, perhaps some menstrual blood that got in a little water on the floor, or at the discovery the ones walking all over Rudy's barely visible shoe prints, or any of the forensic technicians walking through that hall with their booties, in and out of the murder room and out in that hall--it's meaningless as evidence of murder against Raffaele and Amanda, who themselves might have made them at any time without involvement, which is the almost certain conclusion that can be reached being as there's no evidence of either of them getting pure blood on them in the murder room, let alone somehow getting highly diluted blood out of that murder room as I don't recall there being a swimming pool in there, do you?

As for the DNA, well that was a hallway, people walk around in it. It would not be unexpected for there to be copious amounts of trace DNA from those who lived there, and that they didn't do any substrate controls suggests they knew that too.

The only thing the luminol prints prove is there was no clean-up in that hallway and that the prosecution was absolutely desperate to use anything they could. Incidentally, I think perhaps you misunderstood what Hellmann probably meant by why the amount of traces found indicates there was no clean-up: the best indication of a clean-up is that things get cleaned up! That would have taken ten minutes, a mop or sponge and a bottle of bleach in that hall and nothing would have been there. Without bleach all that hemoglobin, (which is what luminol and TMB reacts to) would have been smeared all over the hall and there wouldn't have been those relatively recognizable shapes that they photographed when they laid the luminol down.

Incidentally, they had plenty of luminol hits at Raffaele's, and they found their DNA mixed together, and even DNA of both of them on a knife of Raffaele's. None of that means Raffaele killed Amanda, does it? The whole forensic case is sophistry. ;)

Chris Halkides said...

Dear Alex,

Joseph Neff and Mandy Locke wrote, "The FBI's written policy directed the analyst first to report the positive presumptive test results. If the confirmatory test is negative, the analyst would write, 'Further testing could not confirm the presence of human blood.' It's a pity they waited so long to run the confirmatory test; the hemoglobin might have denatured in the interim. It is also worthwhile to contrast this with the luminol-positive work. I suppose Ms. Stefanoni should have reported "Further testing to confirm the presence of blood was not attempted, because the TMB test was negative." Given that Gregory Taylor was released on the basis of the lack of a disclosure of a negative result with a confirmatory test, it is clear that some courts take confirmatory testing and discovery seriously.

It is not uncommon for forensic technicians to blame a negative result in a confirmatory test on not having enough sample. However, I recently studied two methods of modern confirmatory blood tests. I estimated that the test for immunoglobulin G would detect blood at a dilution of about 600,000-fold and that the test for hemoglobin would detect blood diluted 7 millionfold. The latter estimate is slightly less than the published value.

I have also found a number of different values for the published sensitivities of luminol and tetramethylbenzidine (TMB) to diluted blood. The values for TMB range from 10,000-fold to 1 millionfold. The values for luminol ranged from 200-fold to 100-millionfold. Without wanting to get too bogged down in the details, I would point out that the sensitivity of TMB was reported to increase tenfold (from 10,000-fold to 100,000) just by increasing the time of the reaction from one minute to two minutes.

My take: Luminol may be slightly more sensitive, but TMB is very sensitive itself. Therefore, it is quite a stretch to argue that in every instance where luminol was positive and TMB was negative, that the dilution of blood was just exactly enough to fall into this nebulous region. The negative result with TMB coupled with the failure of the FP to perform confirmatory testing make it unlikely that blood was actually present, as Professor Lednev indicated.

Alex van den Bergh said...

Gosh, that's a mighty lot of words.

Ultimately, however, it all comes down to this.

Firstly, Kaosium has accepted that the Court of Cassation will not deal with the issue of discovery (the allegedly untimely disclosure of the negative blood tests). Thank you! I don't mean to get anyone's knickers in a twist over this; it's just that it's useful to understand what the Court of Cassation may or may not say.

Now, on to the negative blood tests. I understand that both of you believe that the negative tests absolutely indicate that no blood was present. The fact of the matter is, however, that when I read the two verdicts, I am not convinced of this. Indeed, anyone reading the verdicts would have to be convinced of the opposite. After all, the original court wasn't convinced, neither was the prosecution, and, at the time, the defence clearly wasn't either. When dr. Gino stated that the negative blood tests meant that "it could not be said with certainty that blood was present", she is stating that the negative tests might give an (important) indication of the absence of blood, but no absolute certainty.

Conversely, the Appeal Court did seem to be convinced, but its substantiation is faulty, as has been addressed quite fully here.

So, reading the two verdicts, my "conviction" (such as it is), is that a negative blood test is not absolute. I fully understand that you wish to change my mind, but you must realise that's not going to happen simply on the basis of your personal posts.

Kaosium said...

Dr. Gino was was referring to the luminol test when she said that, which is exactly what I tried to get across in my post, a luminol positive is not an absolute, as a matter of fact it cannot determine with certainty that blood is present, only a confirmatory test can, but you do know if it doesn't light up, it's not blood, right?

Same with TMB, it's a natural chemical reaction. If it doesn't turn color, it's not blood. That's why Stefanoni said that (early) and why Hellmann quoted it. What happened was once the TMB negatives were revealed the prosecution simply tried to pretend the blood was diluted below 10k:1, thus the TMB wouldn't react due to not enough hemoglobin being present to cause the reaction.

At that point it doesn't matter though, blood diluted below 10k:1 wouldn't even be visible in a pool of water, it wouldn't cause it to even look barely pink. That can't incriminate anyone and could happen at any time. It completely disproves the possibility of bloody footprints coming out of the murder room, which is what was originally presented at before they got caught hiding those TMB negatives.

Anyway, if you were curious as to why the 'evidence' was dismissed as garbage, this is the best heuristic. It's all like this. Either false, misleading or fraud, and I'm sure you know Cassation doesn't rule on evidence so that hasn't changed. It doesn't matter if you believe me or not, do a little googling or just think the logic of it all the way through and you'll see what I mean. Odds are they're not even diluted blood, but some other substance, but even if they were diluted blood that doesn't matter.

Alex van den Bergh said...

Dear Kaosium,

I'm sorry, but you're clearly in error here.

Of course dr. Gino was talking about the TBM tests (ask Chris, I'm sure he'll agree with me here). After all, the Luminol test was positive, and she's talking about negative test results. Let me again quote what she said (according to the original court):

"Dr. Sarah Gino (...) underlined that the (...) reports which had been made available had shown that a generic diagnosis for blood had been performed and had given a negative result, and therefore it could not be said with certainty that blood was present in the material revealed by Luminol."

So, the Luminol test was (obviously) positive, but the blood test (the TMB test) was negative.

Science really isn't that hard, you know :)

Alex van den Bergh said...

Dear Kaosium,

I'm sorry, this should have been a part of my earlier post. As it is, it'll have to be a new one, all my itself.

You wrote:

"Same with TMB, it's a natural chemical reaction. If it doesn't turn color, it's not blood. That's why Stefanoni said that (early)..."

This is exactly the discussion I've been having with Chris. I pointed out that I didn't think dr. Stefanoni said anything of the sort, and I pointed out why. I then asked Chris to give me some sort of verifiable quote from which it follows that she nevertheless did indeed state something along these lines.

I'll ask you the same question: do you have such a quote?

Chris Halkides said...

Alex, You are the one making a positive claim, namely that the Hellmann court misquoted or misunderstood Ms. (not Dr.) Stefanoni. It is your claim to support, and so far you have not done so (by quoting the trial transcripts for example). Nor have you answered many of the points that Kaosium and I raised.

Alex van den Bergh said...


With all due respect, you do realise that's a bit nonsensical, right?

It is the Appeal Court which expressly states what dr. Stefanoni has commented, not I.

I, in my turn, very much doubt the Appeal Court's assertion in this regard. I have explained why.

If you, or Kaosium, nevertheless believe the Appeal Court is correct, well then, just point that out to me. Give me a verifiable quote.

I'm not essentially arguing with you, you understand; I'm simply interested in whether the Appeal court was or was not right in saying what it did. I don't believe it was; if you believe otherwise, convince me.

That's really all there is to it.

Kaosium said...

Waitaminnit, Alex, are you saying you think Hellmann misquoted Stefanoni or just made that up? Well, let me put it this way, even if he did it's still right!

Thus I highly doubt he did--or would have to. Incidentally, that quote wouldn't have necessarily (and probably didn't) come in reference to this issue, it was probably before the TMB negatives were revealed. When Stefanoni testified she gave a basic overview of the tests used, another example of this is all the quotes from her testimony in Massei regarding the DNA work, including the forensic applications how one can't tell when something was deposited and if it was a mixed sample that it didn't mean it happened at the same time. If you're truly doubtful she said it, that's where I'd look for it, early in her testimony when she's explaining the tests used.

As for Gino's quote, it's a weak way of saying it, but it amounts to the same thing I was saying: obviously them being blood is no certainty if they pass a luminol test and fail a TMB test--it's damned unlikely actually--in fact basically impossible with pure blood. They could have done the tests wrong that's the only real possibility--the others being age which wouldn't apply to six weeks and a rare alkaline chemical reduction agent which isn't present either as the TMB tests right next to one of them on Rudy's shoeprints was positive

However note how she says the presence of blood, because as they later advanced there is one way blood could have been present with a negative TMB on a positive luminol hit, and that's if it was diluted below the TMB threshold. But as I pointed out, that means you're at less than 10k:1 dilution and at that point, who cares?

Take a look at this video, where they're standing and walking all over is where six weeks later they'll be laying down the luminol. All those people in and out of the murder room, bathroom, walking over where Rudy's barely visible bloody footprints were.

Kaosium said...

That started the moment Amanda went home and started taking a shower, continued as Raffaele went through there, Filomena, her boyfriend and buddy, the postal police and the technicians that first came in that didn't notice Rudy's bloody shoeprints. Just one drop of blood getting anywhere there was moisture such as on people's shoes as they came in from the outside, a little water on the bathroom floor where the bathmat was sitting with (diluted BTW) blood on it, or of course for some of them they might well be Rudy himself the night of the murder. This could also have happened any time before the murder, perhaps a drop of blood from Amanda's ear someone's menstrual blood, a cut or something getting a drop in a film of water on the bathroom floor etc. At less than 10k:1 it wouldn't even be visible in the liquid, you couldn't even see pale pink.

However considering how bright those pictures are, odds are high (most are) not blood because being diluted to that extent reduces the amount of hemoglobin that can react to the luminol and give off that pretty glow. Once you get down below 10k:1 it has faded considerably and will continue to do so, of course.

As for whether that quote is in Stefanoni's testimony, I guess you'd have to look. It would be awfully surprising that Hellmann would just make a quote like that up or misquote it and since it's very basic forensic science anyway it's damned unlikely he'd have to, or if he did, it's still not wrong! :)

Again, look at it this way, when they laid the luminol obviously most of that hallway didn't glow, thus do you think there's still a chance there was blood in the part that stayed dark? Well, there is the possibility there was blood there diluted below the ability of luminol to detect it, which is the same thing that's true of any test anywhere and with any test like this one can come up with an unlikely possibility like this, and remember, that's not what they started saying, just what they were reduced to after being caught hiding the negative TMBs and lying about it... ;-)

Chris Halkides said...

Sarah, Alex does not agree with you, but Italian crime journalist Meo Ponte does: "Meo Ponte, an Italian journalist who covered the case for La Repubblica, said that many Italians thought Knox was guilty only because they did not know the details of the case. He described the original trial 'shameful' for convicting Knox.

'To sentence someone for murder, you have to have proof," Ponte told USA TODAY.'"

Chris Halkides said...


Sorry, my previous comment was intended for the other thread. Ms. Stefanoni's comments make sense when applied to any presumptive test, as Kaosium discussed. Presumptive tests should have high sensitivity, and false positives are better than false negatives. The confirmatory test that should follow the presumptive test is intended either to support or to negate (in the case of a false positive) the results of a positive presumptive test. Unfortunately forensic technicians all over the world sometimes get overzealous, as I have documented here

Alex van den Bergh said...

Hi Kaosium and Chris,

Thanks for both your posts.

Kaosium's remark that Stefanoni may actually have said what the Appeal Court stated, but that she said this before the negative TMB test was disclosed, is certainly interesting. However, it's just speculation. The point is that I cannot find anything to convince me of the fact that Stefanoni actually said anything of the sort. That's why I asked you (and asked Chris earlier) to help me out here. I still believe that the Appeal Court simply made a mistake.

The second point I would like to make is that I just cannot believe that the simple fact that a TMB test was negative can actually be conclusive. And to be honest, I don't believe you can, either.

Not in a case such as this, where you have a positive Luminol test and DNA traces, where you know the blood (if there was indeed blood) would have been severely diluted, and where you know that Luminol is more sensitive than TMB. And not when the material you have to work with is very scant indeed, so you will have to save most of it for DNA testing (and not for a TMB test, let alone confirmatory tests). I'm not going to repeat myself here, but clearly neither the prosecution or the defence felt this way, either (you might well remark that dr. Gino was "weak" in her comments, but there would seem to be a good reason for that).

Besides all this, there is nothing I know of - in scientific literature, in particular - to convince me you are right.

Finally, nothing Chris has stated in his post (to which he has linked) can be considered all that convincing, either (sorry about that, Chris!). For example, in Chris's post, the fact that we are, in this particular case, not just talking about a positive Luminol test but also about DNA having been found, is not seriously addressed. On the contrary: he discusses a number of cases that may well be interesting, but that don't seem to be very comparable. When he does switch to this case, he skips quite a few beats. And, in fact, when it all comes down to it, it seems to follow from Chris's own post that whilst a negative TMB test may well (in general) be indicative of the absence of blood, it is, indeed, not conclusive.

As a aside, we have not yet discussed a second part of the Appeal Court's ruling, which is its quote of prof. Tagliabracci. Now I hate to say it, but that's another quote I can't find in the original verdict (not all too surprising, though, since it seems to have been made at a preliminary hearing). The question is: would you agree with Tagliabracci's assessment that a TMB test would be "very sensitive, so much as to give a positive result even with only five red blood cells present"?

If so, can either of you point me to some convincing literature in this regard?

Kaosium said...

Regarding Gino's quote, I may have been unclear and failed to effectively point out the way she stated it as failing the other test and referring to the presence of blood means she was making it in the context of knowing it failed the TMB tests and was saying even then there's other possibilities besides it being diluted blood, notably another substance (which was probably the case).

However once they retreated to the dilution argument the luminol hits became irrelevant anyway, these were not advertised as diluted blood stains, but 'bloody footprints' made in pure blood. As there's no source of where they could have been diluted to that extent in the murder room, at that juncture you know even if they were blood they were transmitted either before the murder with some other blood that perhaps got into a pool or film of water in the bathroom, (or kitchen) or moisture on the bottom of shoes from the outside perhaps at the discovery with all those people tromping through there on top of Rudy's barely visible shoeprints--or Rudy himself after washing his foot off. Diluted blood is not inculpatory, pure blood from the murder room would have been.

As for the literature and the sensitivity of TMB I wrote a post here linking a bunch of them and explaining them, if you don't find what you need in that particular post continue on reading my and Halides1's posts in that thread and odds are you'll learn more about luminol and TMB than you ever wanted to know.

Short version if you're not that interested: those websites promoting the greater sensitivity of luminol take the best lab values for luminol and compare it to field conditions (on varying surfaces) for TMB, the difference is not as enormous as it sounds, nor is it as relevant as they make out. A greater sensitivity doesn't translate to a better chance of detecting pure blood, any of the blood tests can do that, it just means you can pick up blood that has been diluted greater and that often means just a drop or two of blood got into something and tracked around.

The only thing the luminol hits prove is there was no clean-up in that hall, if the presence of Rudy's barely visible shoeprints right next to them wasn't a big enough hint. With bleach (or a similar cleanser that would remove blood traces) they wouldn't have existed, with a cleaner incapable of that they would have had the hemoglobin that the luminol reacts to smeared all over and even the least distinct ones wouldn't have recognizable shapes outside the cleaning pattern.

As for the DNA, in a very real sense those luminol hits serve as a substrate control on the floor in the cottage, as has been noted they found DNA in some of them, and not at all in others, which is what you'd expect if you sampled that floor with people cohabiting anyway.

Kaosium said...

If you don't want to follow the links up there or read all that literature, here's an abstract from a study done to assess whether luminol interferes with PCR DNA testing and the TMB (and phenolphthalin) blood tests:

"This study was designed to test the following factors involved with processing luminol treated bloodstained evidence: 1) The reactivity of other presumptive chemical color tests, phenolphthalin (PT) and tetramethylbenzidine (TMB), following the application of the light emitting luminol presumptive test. 2) The effect of different cleanings of various bloody substrates on the luminol test. 3) The effect of different cleanings of various bloody substrates on the ability to obtain DNA suitable for PCR testing. 4) The ability to extract DNA from luminol treated bloodstained substrates using three extraction techniques. 5) The effect of spraying washed and unwashed bloodstains on various substrates with luminol on the ability to correctly type the DNA using PCR. Our findings indicated that luminol did not adversely effect the PCR testing and did not interfere with the PT and TMB presumptive tests for blood. It was determined that the substrate and the method of cleaning were the major factors affecting DNA yield and the ability to type the bloodstains using PCR based technologies."

Without doing any other reading you should be able to derive from that abstract that using TMB after luminol is not uncommon as there would be no reason to do the study if it was, and scientists wouldn't bother doing studies on the combination if the TMB test was pointless.

Since another positive wouldn't be telling you anything you didn't get from the luminol hit, the only thing that's important is whether you get a negative.

If one can just ignore that negative then why would anyone bother to use the TMB test after luminol in the first place?

I've already give you that answer, and you can find much more exposition on it if you click that first link I posted and follow the discussion as far as you can stomach.

Chris Halkides said...

Dear Alex,

Massei wrote (p. 380), “Amanda (with her feet stained with Meredith’s blood for having been present in her room when she was killed) had gone into Romanelli’s room and into her own [room] leaving traces [which were] highlighted by Luminol…” Here are some problems that Massei did not acknowledge. The luminol print in Amanda’s room does not match her second toe (as can be seen from photos in the Rinaldi report). The footprints in the hallway do not have any DNA. The luminol-positive areas in Filomena’s room are neither footprints nor shoe prints. The prints in the hallway and elsewhere were dilated by the overapplication of luminol. No reference prints were taken from Laura, Filomena, (or from Meredith's body). Therefore, attributing them to any individual is open to question.

With respect a question of mine about the presence of DNA in a sample that tests positive by luminol, Dr. Virkler and Dr. Lednev wrote: “It is correct to assume that DNA profiling is not a confirmatory test for blood because it can be found in so many other things. Just confirming the presence of the victim or suspect's DNA has absolutely no bearing on what type of tissue or fluid it is. There could have been skin cells scattered in a pile of ketchup that would match a person's DNA, but that doesn't make it blood.” Dr. Virkler and Dr. Lednev coauthored an article in Forensic Science International about presumptive and confirmatory tests for fluids. Dr. Lednev served on a White House subcommittee whose “task is to plot the long-term trajectory of forensic science by identifying and prioritizing current and future research, and bridging the gap between discovery and implementation.” I also quoted their criticism of the forensic blood work in this case upthread, and no one rebutted their comments.

IMO any attempt to bring the presence of DNA into the discussion of the identity of the luminol-positive substance(s) is a de facto attempt to turn DNA into a confirmatory test for blood. Even if one does not agree with the statement above, one is still obliged to explain how the absence of Meredith’s DNA in some of the luminol-positive areas should be interpreted differently. It is unclear to me whether or not Massei made this particular error, but it seems to me that you in effect did. The most recent example is when you wrote, “where you have a positive Luminol test and DNA traces…”

To be continued.

Chris Halkides said...

There are several reasons to doubt that the supposedly greater sensitivity of luminol over TMB is the reason why the TMB tests were negative. Let us consider just one, using the following reference: Joanne L. Webb, Jonathan I. Creamer, and Terence I. Quickenden, Luminescence 2006; 21: 214–220. DOI: 10.1002/bio.908 “A comparison of the presumptive luminol test for blood with four non-chemiluminescent forensic techniques”

Hemastix 1:1,000,000 solution
Luminol 1:5,000,000 solution

Hemastix is a commercial version of the TMB test. Suppose that these values are accurate, and luminol is fivefold more sensitive than TMB. For this to be the reason why the TMB failed, the blood would have to be diluted to roughly 2,500,000 in each instance. That’s a pretty narrow window. With respect to Dr. Tagliabracci’s comment about 5 cells, I was able to locate the product literature on hemastix, and the claim a sensitivity of 5-20 cells per microliter. My back-of-the-envelope calculations suggest that a value of 20 cells is in the right ballpark.

Summary of the problems with the work with luminol
There is a lack of reference footprints, and the luminol was overapplied. The luminol-positive areas were tested with TMB, yielding negative results. There was no confirmatory test, despite the sensitivity of modern confirmatory testing in the identification of biological fluids. The DNA forensics did not include substrate controls. The luminol prints in the hallway are all right feet and they don’t form a trail. The luminol work was done on 18 December, and items such as Meredith's mattress had been moved out of her room at some point in the intervening time. The FP did not have removable shoe covers as they moved about the flat (one photo indicates that they stepped in dried blood). As far as I am concerned every piece of evidence collected on this date or later should be tossed. Finally, if one accepts that the print in Amanda’s room does not match her reference print, the whole house of cards starts to wobble.

Alex van den Bergh said...

Hi guys,

I'll try and get back to you tomorrow. But not today, I'm afraid.

Alex van den Bergh said...

As promised, my response.

Firstly, to Kaosium:

1. I have to admit I don't quite follow your thoughts when it comes to dr. Gino. It may just be me, but what she said seems quite clear.

2. As to the "pure blood" versus "diluted blood" argument, I must again admit I can't quite follow your line of reasoning. The original court assumed that, when it comes to the two mixed DNA traces discovered by the use of Luminol, these traces were left by the still slightly bloodied feet of Knox. Obviously, in this assumption, the court also assumed that Knox had washed her feet in the small bathroom before leaving the traces. So clearly, the blood involved would be severely diluted. I do not know to what extent the prosecution at any time presented matters differently; all I know is that the court itself assumed the presence of severely diluted blood. Given, amongst other things, the fact that there were also mixed DNA traces in the bathroom itself, the assumption of the court seems a logical one.

3. When it comes to the greater sensitivity of Luminol over TMB, I rather think that's pretty much a given. You state that "A greater sensitivity (...) just means that you can pick up blood that has been diluted greater" (by which you presumably mean: "more"). Well, indeed; that's why Luminol is more sensitive. A different matter altogether is that, as I understand it, TMB is more selective, which is why (as you state) there are reasons to conduct a TMB test after a Luminol test, if possible.

4. I understand your comments that Luminol doesn't greatly affect the possibility of DNA testing. That's not at issue, though. A problem that, according to dr. Stefanoni, did arise in this case was the fact that TMB testing (Hemastix testing, as Chris said) does severely interfere with DNA testing. In other words, Stefanoni basically had to make a choice: either TMB (Hemastix) or DNA. She chose DNA.

5. I find your comment that "the Luminol hits prove that there is no clean up" a little baffling. To be honest, you don't need to know anything about Luminol (or TMB testing) to understand that there must, indeed, have been some sort of clean-up. Seriously, that's just so obvious that I find the Appeal Court's assumption that there was no clean-up at all to be, well, rather ludicrous. However, that's another matter.

To Chris:

I understand; there is a lack of "reference footprints". I can't see how that matters, though. The two traces that we're talking about were, as I understand it, clearly footprints. The fact that the prints themselves weren't measured or otherwise determined (that is, as to the shape and form of the prints) doesn't change that. Neither does it change the simple fact that both the DNA of Kercher and Knox was found.

As to my question with regard to the Appeal Court's quote of prof. Tagliabracci, you wrote: "With respect to Dr. Tagliabracci’s comment about 5 cells, I was able to locate the product literature on hemastix, and the claim a sensitivity of 5-20 cells per microliter. My back-of-the-envelope calculations suggest that a value of 20 cells is in the right ballpark." Chris, would I be right in assuming that, according to your provisional calculations, Tagliabracci would have been right if he'd said "20 blood cells" instead of "5 blood cells"?

Kaosium said...

Alex, what you don't realize is the Massei court conclusions were merely poorly supported speculation which is why they were completely overturned by the appeals court. It's a post-hoc rationalization and a silly one at that, however that's the way it works in the Italian system, once the verdict is determined a Motivations Report is produced to support the verdict, the sillier and poorly supported it is the more likely it will be overturned, like this one was.

1. What she says supports my position, not yours, you just don't seem to realize it.

2. How did her feet get pure blood on them and where is the evidence of that in the murder room and the hall? Where's any evidence she was in the murder room? There's isn't, is there? So how did and why did she track diluted blood from the murder out of the bathroom? The answer is that's probably not blood and even if it was it's definitely not evidence of being involved in the murder. Thus that contention was silly and unsupported by evidence in a place they looked very hard for it.

3. Progress! :)

4. Stefanoni didn't use Hemastix. Here's an example from Massei (PMF 257-8) of her recovering DNA from something she tested with TMB:

To a question from the Public Prosecutor, she confirmed that a genetic profile of Knox had been extracted from Exhibits 178, 179, 180, and this biological material, which could not be confirmed with certainty as being human blood, could have been, she affirmed, "saliva or skin cells" (page 78); the negative result of the TMB test (tetramethylbenzidine) made it impossible to determine exactly what material had been analysed. She did, in any case, confirm that the profile of Knox had been found ("Certainly, Knox's genetic profile was found", page 79).

Hemastix uses TMB as the reagent (generic term for a chemical that reacts--in this case to blood and similar substances) but not all TMB tests are Hemastix. It's the rubbing of the strip on the sample that interferes with DNA harvesting, to avoid that you take a sample and introduce it to the strip, or you take a sample and put it in a little vial with the TMB! Clever, huh? :)

Kaosium said...

5. You misunderstand, there was no clean-up thus the conclusions of the Massei Court were ludicrous. Cleaning leaves evidence, like clean places, places where cleaning materials can be found, evidence on cleaning materials. There was none of that, thus no clean up, something apparent from the crime scene videos and pictures. Assuming a clean-up for which there is no evidence simply to piece together disparate anomalies to patch together a theory that lacks evidence to support is childish kooky nonsense.

Think about what I said about the hall, you know there was no clean-up there because of the barely visible shoeprints and the luminol hits for the reasons I stated. Massei's attempt at the end of his report is cringeworthy if you understand anything about the subject.

That's why FBI agents and scientists freaked out over the original verdict and the gross misrepresentations made by Stefanoni (especially) and the absurd conclusions of the Massei Court. It's also why the Hellmann Court dismissed all of this as garbage, and why even if they're going to retry her they won't be able to use (most of) this nonsense again.

They're innocent, Alex, it's not even close, it's the police in Perugia and the Italian Courts who're guilty. That's what the evidence actually shows, and what the result will be in the end, a decade or so when the wheels of justice (finally!) grind to a halt.

BTW, are you aware which EU nation lead the ECHR in violations of people's right to a fair trial the seven years before this murder? That wasn't even close either--it was Italy, of course. This is just an example. The ones who know how to evaluate evidence figured that out...


Alex van den Bergh said...

Dear Kaosium,


Alex van den Bergh said...

To Kaosium:

My initial reaction was a simple "gosh". That's not much, and I guess I should respond more fully. So here it is:

Gosh. I don't really know how to respond to that.

I understand you're saying that the original court's verdict was just plain wrong ("ludicrous" and "cringeworthy") and that the Appeal Court's verdict was fine. That's not really an argument, though. You do realise that the current situation is that it's the Appeal Court's verdict that has been overturned by the Court of Cassation, right?

I furthermore understand that you feel the quality of the Italian legal system in general to be severely lacking. Again, though, that's not really an argument.

Both "the Massei report" and "the Hellmann report" are the actual verdicts, you know. Neither are "post-hoc rationalisations".

I don't know whether dr. Stefanoni used a Hemastix test or not; I simply agreed with Chris Halkides when he said that Hemastix is a commercial version of the TMB test. The point here is that a TMB test (such as Hemastix) eats up the material you would otherwise have to conduct DNA testing. You haven't replied to that at all; instead, you respond with a quote that seems to have no bearing at all on the matter.

Now I will immediately add to this that there are two parts to your posts which should, to my mind, certainly be taken seriously. The first is the matter of whether or not a clean-up took place; the second is whether there might be an issue of contamination (i.e., might Kercher's blood have somehow been transposed by "all those people" walking around?). Both are interesting, but the problem here is neither bear any relation to the topic we've been discussing, which is whether or not the Appeal Court's assertion that the two mixed DNA were not left by blood is correct. (In fact, the issue of contamination can only arise if one first accepts that the mixed traces were indeed blood traces.)

Hence my "gosh".

Chris Halkides said...

Alex, You wrote, "(In fact, the issue of contamination can only arise if one first accepts that the mixed traces were indeed blood traces.)" Can you explain what you mean?

Alex van den Bergh said...

Hi Chris,

Of course I can. But surely you know the answer yourself, don't you?

Kaosium wrote:

"That started the moment Amanda went home and started taking a shower, continued as Raffaele went through there, Filomena, her boyfriend and buddy, the postal police and the technicians that first came in that didn't notice Rudy's bloody shoeprints. Just one drop of blood getting anywhere there was moisture such as on people's shoes as they came in from the outside, a little water on the bathroom floor where the bathmat was sitting with (diluted BTW) blood on it, or of course for some of them they might well be Rudy himself the night of the murder. This could also have happened any time before the murder, perhaps a drop of blood from Amanda's ear someone's menstrual blood, a cut or something getting a drop in a film of water on the bathroom floor etc (...)"

In other words, there might have been contamination. That is, it might well be true that the two mixed traces did indeed, amount to blood traces, but the blood might have been "transposed" there by innocent means (means, in other words, that do not inculpate Knox at all).

However, each and every one of these possibilities accepts - indeed, demands - the fact that the mixed DNA traces were, indeed blood. Hence, the issue of such contamination can only arise if one were first to assume that the mixed traces were, indeed, blood.

Chris Halkides said...

Alex, Let me ask you again to clarify what you wrote.

Chris Halkides said...

Alex, You wrote, "The two traces that we're talking about were, as I understand it, clearly footprints. The fact that the prints themselves weren't measured or otherwise determined (that is, as to the shape and form of the prints) doesn't change that. Neither does it change the simple fact that both the DNA of Kercher and Knox was found." I have asked this before, but again, which prints are you talking about? There are amorphous shapes in Filomena's room that have both Amanda's and Meredith's DNA in them, but I have never heard anyone claim that they were in the shape of footprints. There are footprints in Amanda's room, but at least one of them (Rep. 180) doesn't look like Amanda's foot, and none of them has Meredith's DNA. There are three footprints in the hall, but they don't have any DNA. There is a shoe print (not a footprint) in the hall that has mixed DNA (Rep. 183). Therefore, the number of women's footprints that have Meredith's DNA is zero.

Alex van den Bergh said...

Hi Chris,

Am I wrong? I was going, in the main, by the Appeal Court's verdict in this.

From that verdict, I quote the following:

"The prints are of bare feet, detected in Romanelli’s room (176 and 177), in Knox’s room (178, 179, 180), in the corridor (184, rectius [Latin: "more correctly"] 183).


The genetic investigations, conducted by Dr. Stefanoni, biologist of the Scientific Police, gave the following results: 176 trace of Meredith; 177 mixed trace of Meredith and Amanda; 178, 179, 180, biological profile of Amanda, 184 (rectius 183) mixed genetic profile of Meredith and Amanda."

So, what I have always been talking about are traces 177 and 184 (183), which I have always understood to be (a) footprints and (b) traces containing both the DNA of Knox and Kercher.

Am I missing something?

Chris Halkides said...

With respect to Tagliabracchi, the product literature itself says 5-20 cells per microliter. I don't see the quotient between the two numbers as being at all important. Both suggest that TMB is extremely sensitive.

WIth respect to mixed DNA, as far as I know, the five samples of mixed DNA are in the shared bathroom, in a shoe print in the hallway, and in Filomena's room, not in Amanda's room. "The genetic investigations, conducted by Dr. Stefanoni, biologist of the Scientific Police, gave the following results: 176 trace of Meredith; 177 mixed trace of Meredith and Amanda; 178, 179, 180, biological profile of Amanda, 184 (rectius 183) mixed genetic profile of Meredith and Amanda."

The shoe print in the hallway, has been the subject of some confusion; Massei implies that this is Rep. 184 (p. 282), but I think (and maybe Hellman thinks) that Massei should have said Rep. 183. As far as I can determine, Rep. 183 is a shoe print with mixed DNA, and Rep. 184 is a footprint without a DNA profile. I used Charlie Wilkes' selected DNA results file for information on them, and later I found the shoe print itself in Rinaldi's report. The shoe print gave a mixed DNA profile, but the footprint gave no DNA profile. The exact shapes of the luminol-positive areas in Filomena's room is unclear to me, but I have never heard anyone call them footprints prior to reading the passage in Hellmann (which implies that they are), nor have I seen photos to suggest that they are. I have seen one photo that might be the area in question, but it did not resemble a footprint. BTW the Micheli and Massei reports made errors of fact, and if the Hellman report also contains errors of fact, I would be disinclined to interpret any of them as intentional misstatements.

Alex van den Bergh said...


That's interesting! I'll get back to your views as quickly as I can.


Alex van den Bergh said...


Further to your last post, I believe the following may apply.

I think you might well be right: the Appeal Court's assertion that all six traces mentioned are footprints seems pretty shaky. That court, in other words, might have gotten things confused.

From the (translated) Index of Exhibits I quote the following:

"Rep.177 – Sample of presumed blood substance, revealed by luminol, present on the floor situated in the room in use by Filomena ROMANELLI (sample L2) – page 171 A.F./218 R.; (...)
Rep.183 – Sample of presumed blood substance (which shows the shape of a shoe print) revealed by luminol, present on the floor of the corridor situated between the room of the victim Meredith Susanna Cara KERCHER and of Amanda KNOX, with the direction turned toward the door of entry of the corridor (sample L8) – page 138 A.F./223 R.;
Rep.184 – Sample of presumed blood substance (which shows the shape of a bare foot) revealed by luminol, present on the floor of the corridor facing the room of the victim Meredith Susanna Cara KERCHER, with the direction toward the room of this last (sample L9) – page 138 A.F./223 R (...)"

From the original court's verdict the following:

"The traces revealed by Luminol are those labelled 176 to 184 (traces already indicated by the letter L, numbered 1 to 9).
Accordingly, Dr. Stefanoni stated that traces 176 and 177 (L1 and L2) found in the room of Filomena Romanelli had yielded, respectively, the following results: a specimen from Meredith and a mixed specimen from Meredith and Amanda; the traces 178, 179, 180 (L3, L4, L5) all found in Amanda's room had shown Amanda's biological profile; trace 184 (L9), found in the corridor, almost in front of the wall separating Amanda's and Meredith's rooms, had shown a mixed genetic profile attributable to both Meredith and Amanda."

From these two quotes it follows that it could well be true that the first mixed trace (the trace found in Romanelli's room) cannot be ascribed to a bare footprint. It would seem clear, however, that the second trace (the one found in the corridor) would have been left by a foot (and not a shoe).

I cannot explain why the Appeal Court designated all traces to be footprints; neither can I explain why that court felt that, when the original court was addressing trace 184, it was actually talking about trace 183. As I said, it seems the Appeal Court got things confused.

I'd appreciate any further thoughts you might have on this.

Chris Halkides said...

Dear Alex, I am very busy right now, but my previous posts contain some key information. Both courts made mistakes with respect to the footprints and shoe prints. You can see that there are three footprints but one shoe print in the hallway if you leaf through Rinaldi's report (or look at the page numbers I previously provided), which is available to download from the IIP site. It is the shoe print, not any of the footprints, that has the mixed DNA in the hallway. On the issue of the identities of Rep. 183 and 184, I am pretty sure that Massei is wrong and Hellmann is correct.

Alex van den Bergh said...

Hi Chris,

Don't worry, I'll simply await any further comments you might want to make. I'll give the Rinaldi report a go, but I can't read Italian, I'm afraid...

Alex van den Bergh said...


I spent a few merry moments with Google's translation service. Did you know it translates "Raffaele Sollecito" as "Raffaele Reminder"?

In any case, here is what I found.

In the Rinaldi report, mention is made of four "Rilievos" (traces) revealed by the use of Luminol.

There are called, in the report, Rilievo 1, Rilievo 2, Rilievo 6 and Rilievo 7. Three of these (Rilievos 1, 2 and 7) were made by bare footprints; one (Rilievo 6) is a shoeprint.

The report contains a floorplan on which the location of the four traces is marked. It is clear that the traces 6 and 7 are in fairly close proximity; both were found in the corridor next to Kercher's and Knox's rooms. Of the two, the shoeprint (Rilievo 6) is directed towards the front door of the apartment, away from Kercher's room; the footprint (Rilievo 7), however, is directed towards Kercher's room.

With regards to Rilievo 7 (the footprint), the report states that the trace is well-defined, and that the big toe, the metatarsus, the arch and the heel can be distinguished. It concludes that a comparison between the trace and an actual imprint obtained from Knox's foot shows that the trace was "probably" made by Knox's foot.

Besides the traces revealed by Luminol, the report also discusses various other prints. One of these is "Reperto 7" (Exhibit 7), which consists of a pair of shoeprints. These prints were, I believe, also found in the corridor, but I am unaware as to the exact location (they are not marked on Rinaldi's floorplan).

Returning to the (translated) list of exhibits, Rilievo 6 is mentioned as Exhibit (Reperto) nr 183, whilst Rilievo 7 is listed as Exhibit nr. 184. "Exhibit 7" seems to be just that: Exhibit nr. 7.

Now, let's get back to the Appeal Court's verdict. Firstly, I am now convinced that the Appeal Court made a mistake in describing all the traces mentioned as having been made by bare feet (as you yourself already stated). However, I am also fairly convinced the court got further facts wrong as well. In particular, I would assume that the court incorrectly felt that "Exhibit (Reperto) nr. 184" was actually "nr. 183"; furthermore, it also and at the same time seems to have confused Exhibit nr. 184 (called Rilievo 7 in Rinaldi's report) with Exhibit 7 (Reperto 7).

In short, it seems to have made rather a mess of things.

Now clearly, I am going by the documents I know: the two verdicts, the list of exhibits, and the Rinaldi report. You may be aware of information I don't have.

Alex van den Bergh said...

Dear Chris,

As you'll know, the Court of Cassation has released its verdict today.

So we've been sort of superseded by events, I guess.

Nevertheless, if I understand the court's judgment, it doesn't go anywhere near the detail we've been discussing. In that sense, that discussion will still be valid when the new appeal court takes up the matter.

I'll leave it up to you whether you wish to continue the debate.
As for me, I'd like to await a good translation of the court's verdict and take it from there.

Chris Halkides said...

A complete machine translation of RInaldi's report can be found at InjusticeAnywhere. Rep; I83 is the shoe print (Both Massei and Hellman refer to it as a footprint, IIUC). 184 is the footprint, and it has no DNA.

Rinaldi Report

"Survey No. 6 of the Report of Inspection at the address of the Meredith Kercher
18.12.2007: footwear impression found on the corridor from the Baltic Sea Chambers of
KNOX Amanda and Meredith Kercher, oriented output, printed to deposition
blood substance and detected with Luminol, a reproduced picture 4 of photography.
The stamp shows a sufficient definition and represents the entire surface of the sole.
Despite the adequate definition of the general characteristics, the lack of
special features (papillary ridges) and the absence of a reference metric (without which
you can not perform the correct sizing) the footprint is to be considered not useful for
Public Prosecutor at the Court of Perugia
Prosecutor Giuliano Mignini Dr., Replace. Proc
Criminal Procedure nr. RGNR 9066/07 (amendment 21) PROMPT against other Raffaele +"


"The outcome of these technical findings contained in this scheme is precisely in this table. The sample survey called L1 in the minutes of the victim, so no one can say with certainty if it is blood, of course, because it is luminescent luminol but not to ... just having the luminol fluorescence of other possibilities we can only say the victim's genetic profile, and DNA the victim, there is also the sampling of the room always called L2 Romanelli, were both widespread and intense brightness, so there was no evidence of a particular form of luminescence, and such sampling, L2, provided the victim as a result of genetic and Knox, of course, in a mixed genetic, so all these tracks will then be addressed in greater depth in the second half, then we have the sample L3 Knox's room, as well as the other two, which gave genetic profile of Knox.Still, we have the L6, the L7, L8 and L9 to, the only significant result that will be treated later this is precisely the finding 183, L8 sample in the corridor has resulted in more victims Knox, and I ask myself the 'attention on the form that had these samples, these luminosities, we say this was more like, looked like a shoe-shaped, an imprint of the shoe, the other resembled a human foot, as well as the last, the 184, which has no But since no avail"

Alex van den Bergh said...

Hi Chris,

Welcome back! Sorry for the very late reply, but I sort of thought you'd gone AWOL.

I'll get back to your response shortly, I promise.

Alex van den Bergh said...


As far as I can tell, we agree on the following:

Riliveo 6 (the Rinaldi report) = Reperto 183 (the List of Exhibits) = the shoeprint

Riliveo 7 (the Rinaldi report) = Reperto 184 (The List of Exhibits) = the footprint

Now, the only real question would seem to be: did the shoeprint contain a mixed sample of the DNA of Kercher and Knox, or did the footprint?

As far as I know, it was the footprint. I really can't see anything in what you posted to suggest otherwise. Perhaps the quotation you gave with regard to dr. Stefanoni's comments might prove otherwise, but to be frank, I can't make heads or tails out of that (except perhaps the somewhat vague line that: "the other resembled a human foot, as well as the last, the 184, which has no...".)

Do you happen to have dr. Stefanoni's comments in Italian? I'd be happy to try and come up with a better translation. As an aside, where are the comments coming from?

Alex van den Bergh said...

Not having heard from Chris Halkides in a while, I have decided to edit my original article on the basis of the various posts made here.

The change I have made is clearly marked, along with a reason for the edit.

Chris Halkides said...

It seems to me that Stefanoni is saying that the shoe print has the mixed profile, not the footprint. I am very busy right now, but I will comment again when I can.

Chris Halkides said...

The comments I posted from Stefanoni were from the 2009 trial. It seems to me that the first court also misunderstood the shoe print in the hallway as a footprint.

Alex van den Bergh said...

Dear Chris,

I have waited very patiently for any further comments. If you do indeed have any, please post them now.

Chris Halkides said...

Dear Alex,

Was there something in particular you wished to discuss? I have been hoping that you would clarify some of the things you previously said. For example, you still seem to be using DNA as a backdoor confirmatory blood test, but I realize that you do not agree with my interpretation.

In the interim I have been studying the sensitivities of both presumptive and confirmatory blood tests, and my thoughts are found here. I am more firmly convinced than I was before that the forensic community is entirely correct to demand a positive confirmatory blood test before it can be said that a substance has been demonstrated to be blood. Modern day tests are extremely sensitive, as well as less prone to false positives, a known problem with luminol.

Chris Halkides said...

Here is what Stefanoni said: sangue con certezza, naturalmente, perché è luminescente al luminol ma non… appunto avendo il luminol altre possibilità di fluorescenza possiamo soltanto dire profilo genetico della vittima, quindi DNA della vittima; c’è anche la campionatura denominata L2 sempre nella stanza della Romanelli, entrambe erano una luminosità diffusa e intensa, quindi non era evidenziabile una forma particolare luminescente, e quest’altra campionatura, la L2, ha fornito come risultato genetico la vittima e Knox, ovviamente in un misto genetico, quindi tutte queste tracce saranno poi trattate in maniera più approfondita nella seconda parte; poi abbiamo la campionatura L3 nella stanza della Knox, come anche le altre due, che hanno dato profilo genetico della Knox. Ancora, abbiamo la L6, la L7, la L8 e la L9, l’unico risultato di rilievo che sarà appunto trattato successivamente è questo, il reperto 183, campionatura L8 nel corridoio che ha dato come risultato vittima più Knox; e vi pongo l’attenzione anche sulla forma che avevano queste campionature, queste luminescenze, questa era diciamo più simile, ricordava una forma di scarpa, un’impronta di scarpa, le altre ricordavano un piede umano, come anche l’ultima, la 184, che non ha dato però alcun esito. Questo è giusto un riepilogo del test del luminol e dei risultati inerenti l’analisi genetica. Nella stanza Romanelli sono state fatte due campionature, uno ha dato il profilo della vittima, l’altro ha dato un profilo misto vittima più Knox. La stanza della Knox le campionature, tre profili genetici della Knox. Corridoio, quattro campionature, un profilo misto: vittima più Knox. Il soggiorno – angolo cottura è stato negativo al test del luminol, quindi non ha dato una particolare fluorescenza in un particolare punto, e così anche il bagno grande è stato negativo al test. Questo è un riepilogo delle campionature effettuate sul pavimento di tutto l’appartamento della vittima, qui ovviamente vedete scritti, riportati semplicemente i numeri delle campionature, le stanze a cui si riferiscono ed i risultati genetici, i pallini indicano risultato negativo, quindi non c’è stato nessun profilo genetico, la B indica profilo della vittima, quindi tutte queste hanno dato profilo della vittima, come anche queste, queste profilo negativo, quindi non c’è profilo genetico, queste in azzurro sono il corridoio, questa, la 183, appunto abbiamo detto profilo misto vittima più Knox; poi il soggiorno – angolo cottura sono state effettuate tutte queste campionature, sono sei campionature, una è risultata negativa, le altre hanno dato profilo genetico della vittima; stanza Romanelli due campionature, sono quelle del luminol, una di esse ha dato profilo della vittima, l’altro profilo misto: vittima più Knox; le campionature nella stanza della Knox, evidenziate al luminol, tutte e tre il profilo della Knox, quindi in totale su tutto il pavimento della casa sono state effettuate 26 campionature. Passiamo adesso al sopralluogo effettuato nell’appartamento in uso a Sollecito Raffaele, il sopralluogo vi ricordo è stato eseguito in data 13 novembre. Ci sono varie campionature effettuate in vari ambienti, di rilevante, tranne il profilo diciamo di Sollecito Raffaele, non c’è molto se non il misto che si è avuto in una campionatura fatta su un paio di guanti, in gomma di colore fucsia, una di queste campionature… cioè tutte e due le campionature hanno dato come risultato il misto: Sollecito più Knox ma non è sostanza ematica, e così pure anche i reperti prelevati e le campionature effettuate su di esse dalla spugnetta, da un sifone sotto al lavello, la spugnetta ha dato come esito positivo al test genetico il profilo di Sollecito ma non è sostanza ematica; la camera da letto, questa parte di risultati proviene da evidenziazione al luminol, quindi è stato fatto il luminol sulla maniglia esterna della porta, due campionature sul pavimento, è stato ritrovato il profilo genetico misto di Sollecito più Knox, anche se questo misto è un po’ parziale, mancano alcuni alleli di Sollecito Raffaele.

Chris Halkides said...

In "DNA Forensic and Legal Applications" by Lawrence Kobilinsky et al., they include a discussion of luminol. On p. 36 they wrote, "The major benefits of performing a luminol test rarther than one of the colorimetric tests is that one can search large areas very rapidly, and the chemical used does not interfere with any of the other presumptive tests that may be performed following luminol testing. If the result of the presumptive testing is negative, the analysis is terminated. However, if the result is positive, then a more definitive confirmatory test is performed." It appears that the 2015 SCC panel adopted this view.