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Amanda Knox, Raffaele Sollecito and the Red Herring


Alice laughed. “There’s no use trying,” she said: “one can’t believe impossible things.”

“I daresay you haven’t had much practice,” said the Queen. “When I was your age, I always did it for half-an-hour a day. Why, sometimes I’ve believed as many as six impossible things before breakfast.”


One of the key items of evidence in the judicial car-crash that is the Meredith Kercher case is the knife that was removed from Raffaele Sollecito’s flat by the police shortly after her murder.  Nobody thinks it was the murder weapon.  Even the prosecution do not think it was the murder weapon, though they have to pretend they do.

It is so obvious to everyone who has studied the case that it was not the murder weapon that I am going to type it again.  The ‘knife’ was not the murder weapon’.

If the ‘knife’ was not the murder weapon, how did it get to figure in the case at all?  What is the history of this bogus item of evidence?  To understand the place of the knife in the mythology of the case, let us go back to the time when it was collected and understand why it was collected.  Once that is explained, everything else falls into place.

The problem of no evidence

On the night of November 5th/6th 2007 the Public Minister Giuliano Mignini arranged for the interrogation of Amanda Knox and Raffaele Sollecito.  He used a specialist team from Rome – men who were used to breaking tough Mafia suspects.  Mignini knew that this night was his last chance to get something from Knox because her mother was arriving the next day and she would immediately understand what was going on and hire a lawyer for her, as her Italian flatmates had already done.

By the morning of the 6th the Roman team had done their work and Knox, Sollecito and Patrick Lumumba were arrested.  At this point Mignini either believed that he had the perpetrators, or he thought he had malleable suspects that he could slot into his emerging crime scenario.  He declared, ‘case closed’ and hoped he had acted in time to prevent serious damage being caused to Perugia’s student and tourist economy.

There was only one problem at this point.  He had secured coerced statements but no physical evidence tied the suspects to the crime.  DNA results from Meredith’s room did not implicate the people Mignini had arrested.  Amanda Knox was the prize but she had already written a note stating that she had been confused by her interrogation and doubted its veracity.  Her boyfriend Sollecito was expendable.  If he could be pressured he might grab a get out of jail free card and turn against her, dropping the alibi that she was at his apartment all night.  In fact the focus of his interrogation had been to persuade him that he could not be certain than Knox was with him through the night.  Mignini needed to up the pressure on Sollecito.

How the ‘knife’ was chosen

This is what happened next, as recorded by Sollecito in his book, ‘Honor Bound’.  He was taken to his apartment, shoeless and in handcuffs, by several policemen including two called Chiacchiera and Finzi:

“When Finzi came across a drawer full of kitchen knives, he called Chiacchiera over immediately.  He pulled out the first knife that came to hand, a large chopping knife with an eight inch blade.

“Will this knife do?” Finzi asked Chiacchiera.

“Yes, yes, it’s great,” came the answer.

Much later in court, Finzi made no secret of the fact that this was simply a random pick.  He had no reason to select such a knife.  He hadn’t been given any specifics on the murder weapon from the coroner’s report, or anywhere else, and had nothing to go on other than what he called his ‘investigative intuition.”

No other knives were taken.  Officers testified that there was a strong smell of bleach in the apartment and that the knife had looked exceptionally clean.  Italian forensic police scientist Patrizia Stefanoni testified that it had tiny scratches on the side, compatible with intense scrubbing.  The officer chose to take only one knife.  There was at least one other knife in the drawer.  It could have been a bread knife or it could have had a serrated edge.  Neither of the knives in the drawer looked like a murder weapon so why not test both? – Because they didn’t need another knife to make their point.  Any knife would do.  Sollecito was with them.  What was he supposed to think?

So we have a random knife.  The message for Sollecito was clear.  “We control your destiny now and there is nothing you can do about it.  We don’t care about procedure and evidence.  We have decided you are guilty.  We can fix the evidence.  We can pick a random knife from your apartment and make it the murder weapon.  You had better take us seriously and do as we say or you will be in prison for a very long time.”

This was the beginning of a concerted effort by the police and prosecution to apply pressure on Sollecito to try and make him drop his alibi that Knox was with him at his apartment on the night of the murder.  They wanted him to turn on her to secure her conviction.  He was later put in solitary confinement for six months and back channel intermediaries would sound out his family about a ‘deal’ that would see him released at the expense of Knox.  To his eternal credit he never succumbed to this pressure.

Why the ‘knife’ was not the murder weapon

The ‘knife’ had nothing to do with Meredith’s death.  It was too big to fit the outline of a blade that had been imprinted in blood on her bed sheet.  It was too big to have made the wounds in her neck and crucially, the so-called DNA evidence that the prosecution relied on to keep it in play for four years was later proved to have been rye bread starch all along.  Of course a knife that had been used in a murder would have had blood on it.  There was no blood on the ‘knife’.  This is why the police claimed that they had smelled bleach in Sollecito’s apartment – bleach could have been used to clean it.  The problem with this was that bleach would remove and destroy any blood and DNA that might be on it so there would be nothing testable left on the blade.  In truth, the knife blade had not been scrupulously cleaned and there were tiny particles on it, but they were not human DNA.  The smell that the police officers had noticed at Sollecito’s apartment was a common Italian household cleaner called Lysoform.  In court later they were challenged and were compelled to drop the chlorine bleach claim since that was not what they smelled.  The term “clean smell” was agreed instead.  The only DNA that was reliably found was Amanda’s and that was on the handle because she had held the knife when she used it for preparing food.

Prior to DNA testing Stefanoni tested the ‘knife’ for blood with a very sensitive chemical called tetramethylbenzidine (TMB) and it came up negative for blood.  Judge Michelli in the preliminary hearing struggled with this but eventually gave up.  Stefanoni and the prosecution were faced with an impossible conundrum.  If the ‘knife’ had no blood but was the murder weapon, it must have been cleaned.  If it had been cleaned, it could not have Meredith’s DNA on it.  Ergo, any DNA that was found that was claimed to be Meredith’s must be accidental contamination or have been placed there deliberately by someone who was involved in the investigation.

The prosecution forensic scientist, Patrizia Stefanoni cut corners and allowed confirmation bias to cloud her judgement.  She tested samples from the blade for DNA but the results were negative.  There was no DNA on the blade.  At this point she threw all guidelines for testing DNA out of the window.  Stefanoni used what was for her a new technique called low copy number DNA profiling in a lab that was not set up for this type of work and without the right equipment.  The controversy of the ‘knife’  from then on resolves around the testing of one sample, identified as 36B.  This is the sample that Stefanoni claimed was Meredith Kercher’s DNA.

Significantly, Stefanoni’s performance here demonstrates a lack of scientific integrity and a lack of professional ethics that is most disturbing.  Briefly, useful forensic analysis is based on application of established and accepted scientific procedures where analyses are performed in an unbiased manner. Stefanoni conspicuously ignored these most fundamental tenets.  Instead, she spontaneously fabricated an unorthodox method, apparently ‘on the fly’.  She failed to document her method and most conspicuously misrepresented key aspects of her process in court.  Most significantly, she blatantly violated one of the most important commandments of DNA analysis, “Thou shalt never perform PCR DNA analysis of a test sample in a laboratory where one has just previously performed (in this case multiple) PCR analysis (anlayses) of the victim’s DNA”.  This behavior is even worse when one is making up a new process for LCN DNA analysis in a laboratory which is not suitable for any sort of LCN DNA analysis in the first place.  Her performance here renders the entire process completely worthless as any sort of forensic evidence.  These results would never have been allowed into court in the US or the UK, and would most likely have led to having the whole case tossed out during required pretrial hearings of the lab results (which apparently do not exist in Italy).

Large amounts of Meredith’s DNA were already in the lab because many tests from the crime scene had already been carried out.  No negative controls were used.  The alleged match to Meredith’s DNA was worthless because the result was so infinitesimally small (less than 100 picograms, with a picogram being a trillionth of a gram, or 0.000000000001 gram).  The procedures used to get the result Stefanoni needed were deeply flawed.  The specimen taken from the knife was placed in equipment that had already tested Meredith’s DNA and was contaminated at a low level.

The knife itself had no DNA from Meredith Kercher on the blade when it arrived for testing.  How could it have?  It had been picked at random.  The result Stefanoni would claim as evidence of Meredith’s DNA on the knife could have been achieved by testing any random item in the same way – even a knife from her own kitchen, or from yours or mine.  Meredith’s DNA was already in the machine.  Simple!

Crucially, Stefanoni overrode machine controls that were in place to ensure that contamination could not affect her results.  She used up a whole sample in one test, without leaving a control that it could be checked against.  She resisted all attempts by the defence and the court to release full details of her testing records and her lab was not of a standard to allow the type of low copy number testing that she claimed competence for.

The only serious question remaining about Stefanoni’s 36B result is, ‘is this result the product of contamination due to her inept handling of the evidence, or was this result deliberately fabricated’?

None of this mattered at the time because she was prepared to testify to the court that Meredith’s DNA had been found on the knife and she stonewalled all defence requests for the records from her laboratory for over three years.  The full lab records have never been released.

The acquittal trial judge Prato Hellmann ordered an independent review of Stefanoni’s work which confirmed that it had no probative value.  An explanation of this review is here:  http://www.frontiersin.org/journal/10.3389/fgene.2013.00177/full

But the knife was more than a red herring; it was a key part of the prosecution strategy to keep two innocent students in prison when there was no evidence that placed either of them in the room where Meredith had died.

So what of the real, missing, murder weapon?

We know from the imprint in blood on the sheet, that a small knife was used.  The coroner’s report indicated that a short knife had been plunged right in, to the full depth of the blade.  The fatal injury consisted of a series of 3 stab wounds on the left side of Meredith’s neck, all in the same place, in quick succession.  The hilt struck the skin of Meredith on the deepest wound so the length of the blade could not have been as long as that of the kitchen knife found at Sollecito’s.  It was a short knife like the pocket knife Guede had used to keep Christian Tremontano at bay while he escaped from Tremontano’s apartment just over a month earlier.

Had the infamous kitchen knife gone in hilt deep, three times, it would have almost decapitated Meredith; such a blade would have entered the front of her neck and come out of the back.  Amanda Knox quotes in her book “Waiting To Be Heard,” “Professor Torre…explained that in a moment of homicidal frenzy, it would be highly unlikely for a killer to plunge a knife in only halfway…And the odds would rise to impossible when you considered driving a knife in, to precisely the same depth, measurable to a thousandth of an inch, three times in a row.”

Massei, the 2009  trial judge, ruled that the ‘knife’ could not have caused the wound on the opposite side (still inflicted on the neck but on the right side) because of the size of the wound (1 cm and a half with a depth of 4 cm) and the fact that at 4 cm from the tip the width of the blade of the knife is about 3 cm and therefore much larger than the width of the wound (as indicated, 1.5cm).

By November 4th the medical examiner had determined that the fatal wounds came from a weapon like a pocket knife.  This information was promptly passed to the press.  Therefore the officers who intimidated Sollecito at his apartment on November 6th and picked out the ‘murder weapon’ should have already known that it was not the weapon, but of course that was irrelevant to them for the purpose they had embarked on.  The visit was purely an intimidation exercise to pressurise Sollecito into dropping his alibi for Knox.  When this failed, he had to be prosecuted alongside her and the dodgy ‘knife’ had to be kept in play.

The two knife theory

The prosecution had to fabricate a two knife theory in order to include the wrong knife in the crime.  They proposed that in a small bedroom, with four people struggling, two of them had knives and three of them were trying to restrain Meredith, but only one, Rudy Guede, left any trace of himself in the room and no one except for Meredith and Guede had any signs of a struggle on their person.

They were also forced to speculate that Knox was in the habit of carrying the knife everywhere, in her bag, for protection.  Judge Massei refers to this in his report following the 2009 trial.  Is it credible that any twenty year old girl would carry around a knife that size in a bag for self defence?  You would have to be extremely careful all the time when reaching in to get money, a phone or lipstick.  Massei’s theory, like the rest of his report, makes absolutely no sense.  No one would do this.

No records have been published that show that Knox’s bag was checked for damage caused by carrying a knife, or for blood residue if it was returned to Sollecito’s place after the crime.  If it was, we can be sure that no evidence was found.  We also know that all Knox and Sollecito’s clothing was accounted for, so no bloody items were disposed of.  If they had been involved and had used the ‘knife’ Massei also requires us to assume that they would be stupid enough to put it back in the drawer, rather than dispose of it.

The real problem

But the real problem with the knife is not the DNA – of which there is nothing forensically interesting – the issue is that this knife, collected at random from Sollecito’s, has been inextricably linked to motive.  Who takes a knife to a sex-game? Sure, the sex game may ‘go wrong’, but Massei had already ruled on a motive – the motive was Rudy’s and Rudy’s alone, into which allegedly Amanda and Raffaele got swept up in, in a brief ‘choice for evil’.

To the prosecution, having a knife, any knife, was all that mattered.  The fact that it was the wrong size, from the wrong place, without rational explanation for its presence at Meredith’s apartment was irrelevant.  As a piece of evidence, it worked in the first trial.  The two were convicted, largely because of that knife and the knife still takes centre stage now, 6 years down the line.  This is why the new trial judge, Nencini, ordered a test of a particle of approximately the size of one cell, from the ‘knife’ that was referred to by Stefano Conti and Carla Vecchiotti in their assessment of the DNA evidence at the previous trial.

The circumstantial evidence, taken in the round and viewed dispassionately, is conclusive.  That evidence includes, of course, everything that proves Knox and Sollecito had no involvement in the crime.  The ‘knife’ evidence in so far as it relates to Meredith Kercher, was fabricated and nothing of her can ever be found on it except via contamination or corruption.

A spin too far

Like the rest of the ‘evidence’ that is supposed to implicate Amanda Knox and Raffaele Sollecito in Meredith Kercher’s murder, the ‘knife’ is a red herring.  But as we have seen from the confused coverage, the tabloid misinterpretation and confirmation bias that has infected trolls and haters the world over, the ‘knife’ is not going away.  This confusion has even infected the Italian Supreme Court that requires that the evidence that was presented in the case so far be considered, ‘osmotically’.  The problem with this instruction is that every single piece of evidence when properly examined turns out to be nothing, nada, zip, zilch.  The ‘knife’ is no exception, as we have seen.  How many ‘nothings’ does the Supreme Court think it takes to make a ‘something’?  In a case characterised by red herrings, the ‘knife’ is merely the biggest red herring in the tin.

Postscript from molecular biologist Tom Zupancic

Regarding the Kitchen Knife, the bra clasp, and the DNA evidence more generally, the fundamental questions are; ‘what is wrong with this evidence?’, ‘why is this evidence not credible?’ ‘what does this evidence tell an impartial observer about what happened here?’.

The short answer is that this evidence was created using an inept and inappropriate process that generated scientifically meaningless results. These useless results were misrepresented (repeatedly) in court. The evidence, thus, tells us volumes about the individuals who generated and misprepresented the results. The data generated is worthless for drawing any scientifically valid conclusion about the events that transpired at the crime scene.

ie. ‘what is wrong with this evidence?’ It was generated by an inept and inappropriate process. It is not scientifically valid.

‘why is this evidence not credible?’ Again, it was generated by an inept and inappropriate process, but further, the flawed results have been repeatedly misrepresented in court. In particular, multiple elements of the analysis have been falsified, a serious breech of acceptable professional conduct; falsified evidence is inherently not credible.

‘what does this evidence tell an impartial observer about what happened here?’ While the incompetent analyses and distorted misrepresentations of the DNA (knife, bra clasp, mixed DNA) provide no useful or relevant information about the crime, the documented behavior of multiple individuals who created and propagated this misinformation going forward demonstrates a systemic failure characterized by a callous disregard for truth and justice.

In exploring this case the topic of ‘Scientific Misconduct’ in particular was identified as an issue. This problem is widely recognized as a very serious issue in the scientific community. High profile cases of such misconduct in basic research may sometimes even make it into the mainstream media.

My personal favorite quote regarding this sort of thing is one attributed to Abraham Lincoln when he commented on ‘crooks in the US congress’; “you can’t dip clear water from a muddy stream”. The same would go for any sort of human endeavor, I would say.

That said, Scientific Misconduct in Forensic Science can broadly fall into a couple of catgories; ‘falsification of evidence’ and ‘fabrication of evidence’ being most relevant in this case. Where falsification involves modifying or omitting details of results to promote some predetermined interpretation while fabrication involves making the data up from nothing. It must be emphasized that a fundamental issue with interpreting questionable results is understanding whether the individual who generated the questionable results did so purposefully. It is quite difficult to answer such a question. Nevertheless, the formal definition of ‘falsified evidence’, which appears to be most significant in the present case, is investigator intention agnostic. ie. if some presentation of evidence is false, it is falsified, by definition, regardless of whether the investigator created the ‘false’ presentation’ as a result of human error, incompetence, or willful deceit.

For a comprehensive overview of the case go to:  http://groundreport.com/the-murder-of-meredith-kercher/

I have drawn on many sources in writing this article, in particular an article on the ‘knife’ on the Injustice in Perugia website, the Karen Pruett article linked above and comments by many posters on the Injustice Anywhere/Injustice in Perugia forum including TomZ53.  I would also like to acknowledge Amanda Knox and Raffaele Sollecito whose books I have quoted from.  “Life lived somehow for love is life never wasted.”