Knox 'stabbed Kercher in neck as part of satanic rite'

Prosecutor: American delivered fatal blow, then student was strangled

Amanda Knox, an American exchange student, stabbed her British fellow student and flatmate Meredith Kercher in the neck at the culmination of a satanic rite, a prosecutor told a Perugia court yesterday.

Winding up his case against Rudy Guede, another suspect in the killing of 21-year-old Kercher last November, the prosecutor, Giuliano Mignini, added that Mr Guede then strangled her while the third accused, Ms Knox's boyfriend Raffaele Sollecito, held her down.

Earlier, the 22-year-old from Seattle made an emotional plea to the court, apologising for the "confusion" she had caused by her conflicting accounts of what she was doing on the night that Kercher, pictured, died. The American, who is fighting to avoid a possible life sentence for murder, told the closed court she had confessed to being in Kercher's flat when she died – she told investigators that she heard her screams, but only reacted by putting her hands over her ears – because investigators had struck her, called her a liar and threatened her with 30 years in jail if she did not confess. "Meredith was my friend, I had no reason to kill her," she told the judge.

Ms Knox's declaration came as the first trial of the Surrey student's alleged killers entered its final stretch, with Mr Mignini calling for a life sentence for Mr Guede, the only one of the three accused who has admitted all along to having been in the flat when Kercher died.

Mr Guede, a basketball player and small-time drug dealer who has spent most of his life in Perugia, says he had tried and failed to have sex with Kercher, then went to the toilet where he was listening to his iPod at high volume when he heard screams from her bedroom. He says he emerged to see a man who looked like Mr Sollecito coming out of her room. Mr Guede insists that he played no part in the murder.

On the basis of this partial confession Mr Guede was granted a fast-track trial, which sometimes results in shorter sentences. But if he hoped that by incriminating his fellow accused he might get off relatively lightly, the prosecution's demand for a life sentence came as a blow. Mr Mignini is concentrating on the weight of forensic evidence that points to Mr Guede having played an active part in the killing: his bloody handprint on a pillow found underneath Kercher's body, his DNA found on the victim's body, and a bloody bootprint found nearby. Mr Guede's lawyers called expert witnesses to dispute these forensic findings, but Mr Mignini says they failed in the attempt.

Some of Ms Knox's supporters in the US have claimed Mr Guede acted alone in killing Kercher, but from early in the investigation Mr Mignini has maintained that she died after refusing to take part in a drug-fuelled orgy in which the three accused participated. This was the scenario he outlined to the judge.

Other forensic evidence confirms the theory, he maintains: Ms Knox's fingerprints on the kitchen knife, found in Mr Sollecito's flat, that is claimed to be the murder weapon, other fingerprints in Kercher's room and elsewhere in the flat. As well as urging the judge to find Mr Guede guilty, he will also ask him to formally charge Ms Knox and Mr Sollecito with murder. If the judge agrees, their separate, full-length trial for the murder will begin at a later date.