Category: Hoaxes Sollecito etc

Yet Further Additions To My “Justice On Trial”

Posted by James Raper



Click for current edition

Overview

The main evidence phase of Meredith’s case took eight months.

That was from early November 2007 to the end of June 2008 at which point the investigators reported to the supervising magistrate and defense that it was more-or-less complete.

Printed out, the documents in our enormously comprehensive Wiki (which even now has some some further document collection pending) would about fill an 18-wheel truck. Dr Mignini’s 2023 book adds important insights and there will be more before the end of this year.

Which is why my book continues to be a work in progress. There were, when researching the evidence, some issues that did give me pause for thought, and which I did not in fact address in earlier editions.

One of these arose from the following quote from the 5th Chambers’ Motivation.

What is certain is that no traces of blood were found on the knife. Lack of which cannot be traced to meticulous cleaning. As noted by the defence, the knife showed traces of starch, a sign of ordinary domestic use and of cleaning that was anything but meticulous. Not only this, but starch is famous as a substance with a high absorbance rate, thus it is highly likely that, in the event of a stabbing, it would have retained blood traces.

But then I thought, why can lack of blood traces not be connected to meticulous cleaning? Isn’t that, by definition, what meticulous cleaning does?  Has there been lab research on this topic?                   

Would not holding a knife blade under running water from a tap not be effective in removing all trace of fresh blood? I do not know if that would defeat TMB, but I doubt that the issue has ever been put to the test in a lab, and remember that despite 7 samples being swabbed from the knife for genetic analysis (including the handle) Sollecito’s profile was not found, although it was his knife and, according to Knox, he had prepared and cooked fresh fish on the evening that the murder took place. Whether meticulous or not only cleaning is likely to account for the absence of his DNA on the knife.

And yet, the fact that no blood traces were found is worthy of note. Does this decisively rebut, or at least cast some doubt on, any notion that the origin of 36B could be haematological, or that the knife could be the murder weapon? After all you would think so, wouldn’t you? I submit the answer is No. Appealing as it is, such an argument lacks sufficiency for a number of reasons. First of all the sample was not tested for blood (so nothing is proved one way or the other in that respect) but the origin of the sample could also have been non haematological.

But how likely is it that it was not haematological? In fact the likelihood is that it was, even if no blood traces were found elsewhere and, remember, saying that no blood traces were found is not the same as saying that there had been no blood on the knife, merely that the tests were negative, that is no blood was found when the knife was tested. Red blood cells make up 86% of the soft living cell tissue in our bodies and this remarkable fact does make it likely (if unproven) that 36B was blood, or maybe - indeed would have to involve - one of the white cells from which any DNA in blood is obtained.

I am not a forensic biologist, but it seems to me that there is another issue as well.

As for the TMB test, can we place complete reliance upon the negative result as far as the knife is concerned? This was, after all, a kitchen knife, used for normal purposes, such as cutting up vegetables and animal and fish meat. As long as there is haemaglobin then the TMB should detect it. It is a very sensitive test. There is research that shows that TMB (and luminol and phenolphthalein) both work in equal measure on human and animal blood, and fish except for a few examples such as ice fish which have no haemoglobin. The only difference between human and animal haemaglobin is that human haemoglobin produces a more intense colour reaction with the TMB test i.e if it is human the result is going to be a brighter blue.

This is, apparently, because of the greater oxygen carrying capacity of human haemoglobin. That being so, and given the function and purpose of this particular knife, then the negative TMB test can surely be regarded as somewhat remarkable. Had the knife never been used for the preparation of a meal involving fresh meat? According to Knox, it had. Even if in the unlikely event that it was not in regular use to that end it was, according to her, used to prepare fresh fish for a meal on the evening of the murder. It was analysed 6 days after it’s recovery from Sollecito’s apartment, but this passage of time, and even longer, is not of any relevance to the effectiveness of a TMB or to a luminol test.       

The above observations rather backs up what I said about the blade of the knife having been cleaned rather well. If TMB is a test with no limitations then the blade should have produced a positive result, if just for non-human blood.That the TMB test was negative does, I would submit, show it’s limitations in certain situations; it can certainly be argued that it was never going to be effective in this instance both because of the nature of the substrata i.e the smooth metal of the blade, and because the blade had been subjected to cleaning and, one can posit, meticulous cleaning at that, if it was a murder weapon.

So, certainly not decisive for me, but as to whether a lack of proven blood traces convincingly demonstrates that one needs must doubt the relevance of the DNA test on sample 36B, I leave this to your own judgement. There will certainly be those who will want to argue from the foregoing that 36B is contamination. I refer the reader to my comment immediately above where I show that touch transfer and lab contamination as an explanation for 36B are not realistic issues. In any event it is worth noting that the lack of proven blood traces, as the clinching argument against 36B, was never advanced by any court in this case. Rather it was that the DNA test, to be reliable, had to be repeated.

As to the starch issue, yes it does absorb liquids but in reality this observation seems to me to be a bit of a red herring. Remember that the starch was discovered by C&V after microscopic examination of cotton threads taken from the swab of sample H, swabbed from one side of the blade next to the hilt. Sample H had already been tested for blood and the result was negative. However, bear in mind that the wound that bled so much (no doubt when the blade was withdrawn) was 8 cms deep, in relation to a knife with a blade 17.5 cms long. That leaves a further 9.5 cms to be covered with blood. I see no reason, from what we know of the wound and the damage it caused, to assert that it would have been. Furthermore, after the strike, with the victim probably on the ground, one would hold the knife with the blade down. Same if the blade was then held under running water from the tap.

[There were also other swabs taken by C&V (though only two from the blade – E and I) which on cytological analysis appeared to have a structure similar to starch (though not as clear as in sample H) and which they attributed to starch. As part of the same cytological analysis C&V also determined that no cellular material was present in any of the samples, though without any specific biological test other than DNA quantification. One can certainly query the accuracy of their conclusions here bearing in mind that we now know that sample I (on the other side of the blade from H) certainly had DNA in it (which obviously renders the claim that “no cellular material was present” inaccurate, at least as regards sample I)]

Anyway, how do we know that the starch was there on the knife at the time of the murder? It is not improbable that having cleaned the knife it was used again for ordinary domestic use. The starch could also have got there as a consequence of the investigators handling it with latex gloves, which contain traces of the cornstarch powder commonly used with these gloves, and this had been pointed out at the Hellmann appeal.

I have, in various places, and where i can, been posting links to my book on the evidence in this case. The latest link will take you to a copy which is still not as comprehensive as i would have liked. But nevertheless here it is.

Permalink for this post Posted by James Raper on 07/05/23 at 09:21 PM • Permalink for this post • Archived in Hoaxes Sollecito etc • Comments here (3)