Italian prosecutors yesterday demanded life imprisonment for American student Amanda Knox and her ex-boyfriend Raffaele Sollecito for the 2007 murder of Briton Meredith Kercher.

"I was Meredith's friend," Knox exclaimed, her voice choked with emotion, shortly afterward. "I didn't hate her."

The sentencing request was expected as the trial was drawing to a close in the central Italian university town of Perugia, where Kercher, Knox's housemate, died from knife wounds to the neck in what the prosecution portrayed as a drug-fuelled sexual misadventure.

"What I've heard in the last two days is pure fantasy, it's not the reality," the 22-year-old Knox said of the summing up by lead prosecutor Giuliani Mignini and deputy Manuela Comodi.

Ivorian immigrant Rudy Guede has already been convicted separately in the case in a so-called fast-track trial. He is appealing his conviction and 30-year prison sentence.

Mignini's summing up last Friday pushed Knox to tears as he depicted the native of Seattle, Washington, as the driving force in the murder.

Knox "harboured hatred" for Kercher, and led Sollecito, now 25, and in a drug-fuelled sexual assault against her that became "an unstoppable crescendo of violence", Mignini alleged.

In Mignini's reconstruction of the murder on the night of November 1, 2007, Knox dealt the first blow, pushing Kercher's head against the wall, then trying to strangle her and strike her with a knife.

Mignini alleged that Guede held Kercher down while Sollecito and Knox inflicted fatal wounds to her neck.

Police found the 21-year-old from Coulsdon, south of London, the following day, semi-nude in a pool of blood with her throat cut in the house in Perugia, a medieval walled city in central Italy, that she shared with Knox.

DNA and other forensic evidence that linked Knox to the gruesome crime is "irrefutable and well corroborated," Comodi said Saturday.

Criticism by the defence has "missed the target and never went beyond insinuation," she said.

"In any biological analysis there is the inherent risk of deterioration and contamination," she said. "But forensic biologist Patrizia Stefanoni used all the procedures designed to avoid these phenomena, and no one can say the opposite." A hook on Kerchner's bra bearing Sollecito's DNA "was never moved from the room of the crime occupied only by Meredith," she said.

"Sollecito did not live in this house and had not (previously) been in this room."

The murder sparked sensational headlines in Britain, fed by rampant rumours as well as repeated leaks to an eager press corps during the investigation, eclipsing the hard facts that incriminated Knox, Mignini said.

"Detectives seeking fame, bloggers and mystery writers conducted a sort of parallel trial" in the media, he said.

"But the trial is being carried out in this courtroom alone," he added.

Kercher's family are seeking €30 million from the alleged killers.

Knox's part-time employer at the time of the murder, bar owner and musician Patrick Lumumba of the Democratic Republic of Congo, is suing Knox for defamation.

She initially implicated Lumumba in the murder, and Perugia police held him for two weeks before releasing him without charge.

Two judges and six jurors will decide the fate of Knox and Sollecito, who could face life in prison if convicted.

The jury is expected to begin deliberating on December 4, with a verdict expected the following day in the trial that began January 16.