US student Amanda Knox's appeal against her conviction for the murder of British housemate Meredith Kercher is winding up, with prosecutors set to present their final arguments on Friday. Knox was sentenced to 26 years in prison in 2009 but has always protested her innocence, and the appeal hearing has cast serious doubts on the DNA evidence that helped convict her and her Italian boyfriend Raffaele Sollecito. In their two-day summary beginning on Friday, the prosecution is expected to insist on the reliability of the original forensic analysis which found condemning traces of the lovers' DNA on the murder weapon and a torn bra clp. They are also expected to recap evidence used in the first trial to place the pair at the scene, from bloody footprints to the homeless man who claims he saw Knox and Sollecito on the night of the murder, undermining their alibis. During police questioning in the days after the gruesome killing, Knox said she had been in the house at the time of the murder and had heard Kercher's screams. She also identified a bar owner, Patrice Lumumba, as the murderer. Lumumba was subsequently found to have a rock-solid alibi and Knox said she had been struck by a police officer and had spoken without a lawyer present. Kercher, 21, an exchange student from Leeds University, was found half-naked with her throat slashed in a pool of blood in her bedroom in the cottage that she shared with Knox in the medieval town of Perugia on November 2, 2007. Prosecutors at the original trial said the murder was the result of a drug-fuelled sexual assault by Knox, Sollecito, and a third person, Rudy Guede, who has been convicted separately and is serving a 16-year sentence. Guede, who denies murder but admits having sex with Kercher that night, also said at the appeal trial that he believes Knox and Sollecito are guilty. The original trial sparked a media frenzy, with Knox portrayed as a lascivious party girl whose angelic features masked a devilish interior. But when independent experts called in by the appeal judge cast doubts on the original forensic procedures, some tabloid media turned to supporting the blonde Seattle native, heaping criticism on the Italian judicial system. Police who had attended the crime scene were accused by the defence of failing to follow international procedures after they were captured on film contaminating the DNA traces by using dirty gloves to collect the evidence. The appeal began in December 2010. Next week the court will hear closing arguments from Francesco Maresca, the Kercher family's lawyer, as well as the final summing up by the defence. The result of the appeal is expected either next week or the week after.