US student and ex-boyfriend hope unreliable DNA evidence will see their conviction for Meredith Kercher’s murder overturned The answer could be complex. But the question before the court as the appeal by Amanda Knox and her ex-boyfriend Raffaele Sollecito enters its closing stages on Friday is simple enough: what, if anything, remains of the prosecution case that they murdered the British student Meredith Kercher ? A third person, Rudy Guede, a small-time drugs trafficker from Ivory Coast, has been convicted of murdering Kercher . Evidence of his presence at the murder scene in Perugia four years ago was discovered only after the American student, then 20, and the Italian Sollecito, then 23, had been arrested. The sole forensic evidence directly linking either of the appellants to the bedroom in which Kercher, 21, was found dead was a trace of DNA, identified as Sollecito’s, on the British student’s bra clip. The other crucial support for the prosecution’s claim that Kercher died resisting a four-way sex game was a trace of the victim’s DNA on a knife in Sollecito’s kitchen that had also been handled by his girlfriend. But in June, two independent court-appointed experts dismissed both pieces of evidence as unreliable. The bra clip DNA, overlooked by police for more than six weeks, could have come from contamination, while the knife trace might not have been Kercher’s. Knox’s stepfather, Chris Mellas, said: “She’s starting to think, maybe, this time she can actually do it; actually get out. She’s allowing herself just a little bit of hope.” Barbie Latza Nadeau, the author of Angel Face: The True Story of Student Killer Amanda Knox, agrees that “too many mistakes were made for this to be a clean conviction”. But she thinks the appellants’ tentative optimism may be misplaced. “Knox and Sollecito were convicted with more than 400 pages of reasoning [by the judges], of which less than 25% was devoted to DNA.” Steve Moore, a retired FBI agent who is one of Knox’s most impassioned supporters, counters that “My heart accounts for less than 5% of my body. But it’s the part without which I cannot live. Nothing [in the trial verdict] makes sense if the DNA doesn’t hold up.” Sending Knox and Sollecito for trial in 2008, judge Paolo Micheli acknowledged the improbability of a murder agreed in a matter of hours between three people, two of whom – Guede and Sollecito – were not even known to have met. But, in a crucial passage, he added that if the forensic evidence put them all in the room “it is not essential to find the telephone call with which an appointment was fixed with Guede … nor the witness who remembered or photographed their meeting”. By the same reckoning, without Knox and Sollecito at the crime scene, no amount of circumstantial evidence can uphold their conviction. In its efforts to put them back there, Mellas believes, the prosecution may return to the question of the “bloodied” footprints. Using luminol , a chemical that glows blue when it encounters an oxidant such as the iron in haemoglobin, forensic experts believed that in the corridor outside Kercher’s room they had found footprints belonging to Knox which showed she had stepped in the victim’s blood. But Luminol also reacts to bleach and, says Mellas, a more precise test came back negative: “All you can say is that they found some footprints on the floor of the house where she lived.” Knox testified that, the morning after the killing, she returned from Sollecito’s flat and, unaware Kercher was lying dead just metres away, took a shower before leaving. “She probably rehydrated some floor cleaner after her shower,” says her stepfather. Latza Nadeau argues that non-forensic evidence could still weigh heavily with the two professional and six lay judges. Top of her list is the statement Knox made to police which led to her arrest: she said she was in the house, that she heard Kercher’s screams and named the killer as Patrick Lumumba, a man who ran a local bar and was later cleared of any involvement. Her statement, which she immediately withdrew, claiming it had been made under duress, was ruled inadmissible. Yet it was cited at the trial because it was central to an action for damages by Lumumba, and, since he is also joined to the appeal proceedings, could feature again in the closing arguments that begin on Friday. An equally contentious issue is the evidence of a break-in at the flat. The appellants say it is genuine and bears out their explanation: that Guede was burgling the house when he was surprised by Kercher; that he tried to rape her and, when she resisted, killed her. The prosecutors claim the evidence was faked. They point to the fact that nothing was stolen and that one of Knox and Kercher’s Italian flatmates testified that she found shattered glass on top of her rumpled bedclothes, suggesting her room was ransacked before the window was smashed. Finally, there is the allegedly suspicious behaviour of Knox and Sollecito after the crime. On the night of the murder they both switched off their mobiles (Knox for the first time since buying an Italian sim card) and switched them on again the following morning at around 6.30am, though they said they slept late. Not even Moore has an answer for it. But he says: “Anything could explain that. That is not murder evidence.” Amanda Knox Meredith Kercher Italy United States Meredith Case John Hooper guardian.co.uk