Previously undetected bloodstained footprints have been found at the cottage in Perugia where Meredith Kercher was murdered last November, it was reported today.

Lawyers for Amanda Knox, the American suspect in the murder of the British student, had said that they would argue at a hearing next week to review her detention that she should released from jail and put under house arrest.

This prospect appears to have receded after the accusation by another suspect that both Ms Knox and her Italian boyfriend were at the scene of the crime.

Joe Tacopina, an Italo-American lawyer advising Ms Knox's parents, had said that defence lawyers would argue at a review hearing at the Supreme Court in Rome next Tuesday that she should be placed under house arrest because the evidence against her was flawed or circumstantial.

However Rudy Hermann Guede, an Ivory Coast immigrant being held on suspicion of involvement, told investigators yesterday that he had seen both Amanda Knox and Raffaele Sollecito, her boyfriend, at the cottage on the night of the murder.

All three are in custody on suspicion of having sexually assaulted and murdered Ms Kercher, who was found dead at the cottage that she shared with Ms Knox and two female Italian students on the night of November 1.

Today lawyers for Mr Sollecito dismissed Mr Guede's allegation as “unfounded and untrustworthy”. They said that “once again” they had learnt of the new testimony from the press.

Panorama news magazine, in its edition to be published tomorrow, reports that police have found seven new bloodstains at the crime scene, “which could prove crucial”. The stains — revealed by the chemical luminol and now being tested to identify them — included bloody footprints in both Ms Knox's and Ms Kercher's bedrooms as well as in the corridor, the report said.

Mr Guede, who was extradited back to Italy after being arrested in Germany when caught travelling on a train without a ticket, has admitted that he was at the cottage and had sex with Ms Kercher on the night she died, but denies murdering her. The Ansa news agency said that he had decided to speak out because the two other suspects had “more or less explicitly” accused Guede of being responsible for the murder.

Ms Kercher, from Croydon in Surrey, was found semi-naked and with her throat cut in her bedroom of the whitewashed hillside cottage nearly five months ago. A student at Leeds University, she had arrived in Perugia last August as part of an EU Erasmus exchange programme.

Mr Guede, who says he was in the cottage bathroom when an intruder entered, told investigators: “When I came out of the bathroom I saw a male figure. I put my hand on his shoulder and he had a knife in his hand.”

In testimony in December, he said that he had not seen the man's face clearly, but in his evidence to investigaors yesterday he said it was Mr Sollecito. He added: “I also heard Amanda Knox. She was at the door — I saw her there.”

He said that Ms Kercher and Ms Knox “hated each other” and had had a row over money: “Meredith accused Amanda of stealing 250 euro from her drawer.”

Giuliano Mignini, the chief investigating magistrate, said that Mr Guede's testimony was “very, very useful to the investigation”. Another prosecution source said that it was “a breakthrough, the first time that one of the suspects has directly blamed the others”.

Times Recommends

• UN may halt 400-year-old 'freedom of the seas'
• Where the Rosetta belongs can’t be set in stone
• Gas deal on hold, but Ukraine may pay in the end