PERUGIA, Italy - Closing arguments are set to begin Friday in the case of murdered British student Meredith Kercher, whose body was found more than two years ago at the Italian villa she shared with her American roommate, former University of Washington student Amanda Knox.
The trial of Knox, 22, and her former Italian boyfriend, Raffaele Sollecito, 26, started in January, with both accused of sexual assault and murder. They deny the charges.
Kercher's partially-dressed body was discovered November 2, 2007, under a duvet on the floor by her bed, covered in blood. She had suffered a stab wound to her neck.
The case immediately thrust Knox and Sollecito in the spotlight, with prosecutors saying the 21-year-old Kercher died in a "drug-fueled sex game" the night before with Knox and two men.
Police arrested Knox and Sollecito soon afterward, along with Ivory Coast native Rudy Guede. Guede opted for a separate, fast-track trial and was convicted of murder and attempted sexual assault in October 2008.
The court sentenced Guede to 30 years in prison; he launched an appeal of the verdict this week.
The key piece of evidence against Knox is a 6 1/2-inch kitchen knife that prosecutors say was used to slit Kercher's throat. The knife belonged to Sollecito and was found at his apartment with Knox's DNA on the handle and Kercher's DNA on the blade, according to a source close to the prosecution who did not want to be identified discussing an ongoing case.
Kercher had never been to Sollecito's apartment and wouldn't have come in contact with the knife, which shows it played a role in the murder, the source said.
Experts testifying for the defense, however, say there is no way the knife could be the murder weapon because it wouldn't have made the wounds on Kercher's body.
Anne Bremner, a lawyer and former prosecutor working with the group Friends of Amanda, told CNN the knife had been improperly handled by investigators, leading to questions about the validity of the DNA evidence.
Another defense expert, geneticist and private coroner Sarah Gino, testified that the DNA sample on the knife was too small to be definitive.
On the night Kercher was killed, Knox and Sollecito say they were at his house watching a movie and smoking marijuana.
Their recollection of events, they admitted, was hazy from the drugs, but both swore they went back to the house the next morning. Knox says she was unable to gain entry, and so she called police.
Prosecutors also pointed to what they say is a confession by Knox -- but Knox later said any apparent admission that she was at the scene was made when investigators told her to imagine what she might have seen had she been there.
The argument became moot when a higher court ruled the alleged confession could not be used because the statement was made without an attorney or translator present.
Bremner says the case against Knox is filled with flawed forensics. She said Kercher's bra clasp -- which was found on the floor and contained Sollecito's DNA -- was handled so much that it turned from white to black.
The clasp -- the only evidence that places Sollecito at the scene -- is now tainted, Bremner said.
Crime scene video shows investigators picking up and dropping hairs, not wearing gloves, and throwing evidence aside, Bremner said.
The prosecution source maintains the crime scene was handled properly.
Kercher had only been away from home for two months when she was killed. The Leeds University student was studying European politics and Italian in Perugia.
Earlier this month, Kercher's parents released a statement commemorating the second anniversary of her death, saying they "still miss her more than ever."
"We can only hope now that a conclusion is reached in the next five weeks, so that we can finally dedicate ourselves to remember Meredith for the person that all of us knew and not as a victim or as a news item," they said.
Knox's parents have also spoken out, proclaiming their daughter's innocence and saying she was unfairly labeled a suspect early on.
Closing arguments at the Tribunale di Perugia are not expected to last more than a day. The jury is due to begin deliberating December 4.
In his appeal on Wednesday, Guede, 22, said he saw Knox fleeing the murder scene with a man he could not identify, according to Italy's ANSA news agency.
He said he was at Kercher's house the night of November 1, 2007, and was in the bathroom when Knox walked in and argued with Kercher about money, according to ANSA.
He said he then started listening to music on his iPod but "halfway through the third track I heard a piercing scream," Guede said, according to ANSA.
"I rushed out and I saw a male figure," Guede said. "It all happened in a flash. This person tried to stab me. I toppled back onto the floor."
Guede said he looked out the window and saw "Amanda's shape" running away.
Guede was arrested after blood and other traces in the murder house and on Kercher's body matched his DNA, but Guede said he had simply tried to help stop the bleeding, according to ANSA.
His testimony cannot be used in the trial of Knox and Sollecito, ANSA reported, citing legal experts.