It's not right to say there is ‘no evidence’ in the case against Amanda Knox. There's plenty

The DNA alone is enough to raise questions

The verdict handed down yesterday at the new appeal trial for Amanda Knox and her former Italian boyfriend, Raffaele Sollecito, accused of the murder of British citizen Meredith Kercher in Italy in November 2007, may come as a surprise to those whose view of the case has been affected by an international media blitz based on the oft-repeated claim “There is no evidence”. Many believe that Rudy Guede, convicted in October 2008 for participating in the murder, acted alone.

There is, however, copious evidence to consider: the DNA alone is enough to raise questions. Leaving aside much of it, let’s focus for a moment on three key pieces of DNA evidence and present them from both sides, just as the jury may have heard them spoken of in court.

First – the bra clasp. The part of the victim’s bra containing the hooks had been ripped or slashed from the rest of her bra. Not immediately collected on that first day after the murder, it remained in the room in a sealed house for six weeks before being sent to the lab in December. There, it was tested and found to contain a large sample of Meredith’s DNA, together with a smaller but clearly visible contribution from Sollecito. The defence objections: firstly, between the two searches, objects in the crime room had been moved around, and indeed the bra clasp was found about a metre away from its original position. Secondly, apart from ‘alleles’ - genetic traces - of Meredith and Sollecito on the clasp, there were a few unidentifiable extra ones. Putting these two facts together, the defence pointed out that Sollecito’s DNA on the bra clasp could have been a consequence of a careless police technician stepping on Sollecito’s DNA elsewhere in the flat and then entering the room and stepping on the bra clasp, even though no DNA of Sollecito was found anywhere else in the house except on a single cigarette butt in the ashtray.

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Second – the mixed stain. Although not visible to the naked eye, the chemical Luminol which flashes blue on contact with blood revealed a spot in the room of the flatmate whose window had been smashed and room rifled. Swabbing the spot produced a mixture of Amanda and Meredith’s DNA. This is a clear proof that the murderer entered that bedroom after the murder, as someone must have brought Meredith’s blood into the room, contradicting the defence theory that Rudy Guede broke into the house and then committed the murder. The usual defence explanation for mixed DNA stains in the bathroom and corridor, namely that the house would have been coated in Amanda’s DNA given that she lived there, does not necessarily apply to a flatmate’s bedroom. It is much harder to leave traces of DNA than is commonly conceived, and hardly any of Amanda's DNA was found in her own room - where she surely spent a lot more time than in her flatmate's.

Lastly – the knife. Days after the murder, a large kitchen knife was seized in Raffaele’s flat, where Meredith had never set foot. Police geneticist, Patrizia Stefanoni, swabbed spots on the blade of the knife and on the handle in the knife’s first DNA Test. One spot in particular attracted her attention: a visible scratch on the flat of the blade. The swab taken from this scratch yielded a positive ID for Meredith Kercher. By the third trial, when a new attempt was made to collect DNA from the knife (which had been swabbed again during the appeal trial, though no tests were then conducted) there was no match to Meredith – a result welcomed by Knox's defence team, though it did not in fact impact on the findings of the first trial.

Meredith Kercher, who was murdered in 2007 (AP)

Stefanoni’s test – she only conducted the first - came under strong fire in the courtroom. Two independent expert witnesses called in for the appeal against Knox and Sollecito’s original 2009 conviction stated that she had not worked in conformity with standard international protocol. Indeed, standard protocol for DNA testing involves three steps: first determining how much DNA is in a sample, secondly amplification, which reproduces the sample millions of times, and thirdly electrophoresis which produces the familiar DNA graphs showing peaks in the location of an individual’s alleles. Under cross-examination, Stefanoni explained that quantification had given a result of “too low” as the machine she used that day was not the most sensitive one in the lab.

Knowing that samples undetectable by the machine can still be sufficient to yield positive results, she chose to continue with testing. At the second stage of testing, amplification, a sample will normally be split into two or more pieces in order to run independent tests. But knowing that the sample was small, Stefanoni feared that cutting it in two would yield no result at all, and chose to amplify the entire sample in one unrepeatable test. The end result was a perfect match to Meredith Kercher.

Knox’s supporters have claimed since the beginning that the accusations levied against her are based on the Italian justice system’s hatred of a pretty, American girl who likes parties and having sex. And whilst both parties protest their innocence , Thursday’s decision shows that there is real evidence against her and Sollecito, that cannot be ignored.