There is no evidence that British student Meredith Kercher was sexually assaulted before being killed, according to a new official report into her murder.

The claim appears to contradict the case so far established by Italian police.

Kercher, 21, an exchange student studying in Perugia, Italy, was found dead in the bedroom of her flat on Nov. 3.

Three people, including her American flatmate Amanda Knox, remain in custody accused of involvement in her murder.

Police have maintained that they believe she died of a stab wound while resisting a sexual assault.

Knox, her Italian boyfriend Rafaelle Sollecito, and Ivory Coast national Rudy Hermann Guede have all denied involvement.

A new report by three forensic experts, requested by the judge in the case, questions whether there was any sexual activity.

Sky's Nick Pisa, in Rome, said: "In their conclusions the experts say there is no evidence to suggest that Meredith had any form of sexual activity, whether consensual or not, leading up to her death.

"The three people being held are being held on suspicion of sexual violence."

He said the new report also widened the potential time scale for her murder and suggested she had died of ashpyxiation from blood — apparently from a knife wound — as well as strangulation.

The report says that of three knives seized from Sollecito, one is considered compatible with a wound found on Meredith's body.

The three suspects are expected to appear in court for their next hearing on Saturday.