A new witness in the investigation into the death of Meredith Kercher at her student house in Perugia last November says that he saw all three suspects — Amanda Knox, Raffaele Sollecito and Rudy Guede — at the house on Hallowe’en, the night before the murder, and that Ms Knox threatened him with a knife.

Prosecutors say that the evidence is crucial because it appears to demolish the claim of Mr Sollecito, Ms Knox’s Italian boyfriend, and Mr Guede, a small-time drug dealer from the Ivory Coast who has joint Italian nationality, that they do not know each other.

It also undermines Ms Knox’s denial that she carried a knife, and reinforces police suspicions that she could have been the murderer. Ms Kercher was found half-naked with her throat cut on November 2 at the whitewashed house that she shared with Ms Knox, a student from Seattle, and two Italian female students.

The testimony also reinforces thetheory that the murder was premeditated. “It suggests that on Hallowe’en night, October 31, the three were already together and thinking of an act of violence,” one source said.

New witness 'saw Meredith suspects together'

Amanda Knox, Raffaele Sollecito and Rudy Guede were see at the house in Perugia where the American student died

Multimedia

• Murder in Perugia

BACKGROUND

• Meredith Kercher: Q&A

• New DNA not from Meredith suspects

• Timings crucial to Kercher murder investigation

Ms Knox, Mr Sollecito and Mr Guede are all in prison in Perugia and can be held for up to a year before charges are brought. Police say that a kitchen knife found at Mr Sollecito’s flat has Ms Knox’s DNA near the handle and that of Ms Kercher at the tip.

The DNA of both Mr Sollecito and Mr Guede have been found on fragments of Ms Kercher’s bra, and Mr Guede’s DNA has been detected on Ms Kercher’s body and her pillow.

Ms Knox and Mr Sollecito continue to deny that they were at the cottage on the night of the murder. Mr Guede, who was extradited to Italy from Germany, admits that he was there but claims that he fought with “the real killer”, whom he has yet to identify.

The new witness, an Albanian who lives in Perugia, told police that about 8 o’clock on the night before Ms Kercher was killed he parked his car near the cottage, but in doing so scraped the rubbish bins at the gates. He told investigators: “It was dark and pouring with rain, but I stopped the car, put the hazard lights on and got out to see if I had damaged the car. Suddenly two young people came out. It was them, Raffaele and Amanda. They seemed as if they were looking for a quarrel, they were shouting.

“We began arguing and at a certain point Amanda pulled out a knife and started waving it around in an aggressive way. She was shouting and pointing the knife at me.

“I’m quite certain it was her, and the guy with her was Raffaele Sollecito.”

The witness said that he was scared. “I was ready to run back to my car when out of nowhere in the dark another guy turned up, a black man. It was the Ivory Coast guy, Rudy.” He said that he did not know any of the three at the time, “but I recognised them afterwards when I saw their photographs in all the newspapers”.

Police said that the unnamed Albanian had residence and work permits and was considered “a reliable witness”. He asked to see Giuliano Mignini, the chief investigating magistrate, last week, accompanied by a lawyer. He acknowledged that nearly three months had passed but told Mr Mignini: “I was very frightened all these weeks. I thought I would not be believed as a foreigner and might be suspected myself. That’s why I haven’t come to see you before. But now I’ve decided to tell you everything I saw.”

Scientific evidence suggests that Ms Kercher died around midnight, having bled to death slowly. Mr Guede has indicated that Ms Kercher accused Ms Knox of stealing cash from her room to pay for drugs. Ms Knox and Mr Sollecito have admitted that they spent the day of the murder smoking hashish.

In addition, the two women had allegedly fallen out over the job of part-time bar assistant at a pub owned by Diya “Patrick” Lumumba, a Congolese musician. Mr Lumumba has said that he dismissed Ms Knox because she spent all her time flirting with male customers, and asked Ms Kercher if she would like the job instead.

Ms Knox initially accused Mr Lumumba of the murder, but police concluded that she had falsely accused him to deflect attention from Mr Guede. Mr Lumumba remains officially under investigation.

Times Recommends

• Both sides blame US for worsening relations
• Stieg Larsson: losing the plot over his cash
• Odd creature paralysed by incompatible parts