Police investigating the murder of British exchange student Meredith Kercher in Italy have found mystery traces of DNA on her bra, it was revealed today.
The three traces - believed to be from two males and a female - do not match up with any of the three suspects currently being held over the 21-year-old's death.
The discovery will prompt speculation that somebody else may have been involved in the killing, though one of the suspect's lawyers said police were not making that assumption.
Miss Kercher's American housemate Amanda Knox, 20, her Italian boyfriend Raffaele Sollecito, 23, and Ivorian Rudy Guede, 21, are all in prison near Perugia accused of sexually assaulting and murdering the Leeds University student from Coulsdon, Surrey, on the night of November 1 last year.
Miss Kercher was found at her home in Perugia with her throat slit and police said there was evidence of a violent sexual encounter.
The new discovery was made by forensics officers analysing one of the victim's bras that was found at the house on Via della Pergola.
They had already identified DNA belonging to Guede and Sollecito on the garment.
Vittorio Lombardo, one of Guede's lawyers, said: "We received information from the police that they had found three more traces of DNA on the bra, two masculine and one feminine.
"They said the traces do not match up with Rudy or the other two suspects, but are not jumping to the conclusion that it indicates the presence of another killer.
"It is more likely to have come from cross-contamination. Meredith shared the house with other people, so the traces could have come from any of them or their visitors.
"It is said the washing machine was not as clean as it might have been, for example, so the traces could have come from there.
"As far as we are concerned it doesn't change our case."
Police said the discovery of Sollecito's DNA on the bra earlier this month means they now have evidence putting all three suspects at the scene of the crime.
Guede's DNA was found on Miss Kercher's body and his handprint was found on a cushion, as well as his DNA being on the bra.
Traces of Knox's blood were found on a tap in the bathroom.