'Student killed after refusing sex'

Officers spoke out about her death following the arrests of the student's female flatmate Amanda Knox, 20, and two men, after she reportedly broke down and confessed to the crime.

The three - who are all being held on suspicion of conspiracy to commit manslaughter and to commit sexual violence - were dramatically arrested in raids in Perugia early on Tuesday morning.

The breakthrough follows four days of intensive investigation since Miss Kercher's body was found last Friday in her bedroom at the house she shared with Knox and two others on the Viale Sant'Angelo, not far from the city centre. The Leeds University student, 21, from Coulsdon, south London, was partially clothed and her throat had been cut.

Italian news agency Ansa reported that detectives swooped after Knox, also a student, apparently broke down during police questioning and confessed. It named the other two suspects as Italian student Rafaelle Sollecito, 24 - who is believed to be Knox's boyfriend - and Lumumba Diya, 37, from the Congo.

Sollecito was thought to be finishing his degree in the city and Diya, who is also known by the name Patrick, had been in the country since 1988 and had a regular work permit.

In a press conference later, detectives confirmed fears that Miss Kercher appeared to have been killed when a sexual encounter went horrifically wrong. Perugia's police chief Arturo De Felice told reporters the student had died fighting off a sexual attack. He refused to elaborate further on the circumstances of her death but stressed that she was "morally innocent" and was a "victim and nothing more".

Sky News also quoted interior minister Giuliano Amato as saying: "It's an ugly story in which people which this girl had in her home - friends - tried to force her into relations which she didn't want."

When asked by journalists whether one of the three people being questioned had confessed to the crime, the police said this was a "valid hypothesis", the BBC News website said.

Officers said the arrests meant they had closed the case into Miss Kercher's murder, Ansa also reported.