Rudy Hermann Guede, the Ivory Coast immigrant suspected of involvement in the murder of Meredith Kercher in Perugia, has claimed that two people carried out the attack, one of whom he was “confident” he would be able to recognise.

Mr Guede, 20, who has joint Italian nationality, is awaiting extradition to Italy from Germany, where he was arrested after the killing of Ms Kercher on November 1. Legal sources said he could be extradited tomorrow or Friday.

He has admitted to German police and his Italian defence lawyers that he was at the cottage where Ms Kercher was murdered on the evening of November 1, but insists that he did not kill her. He claims an Italian man he did not know, described as shorter than himself and with brown hair, attacked Ms Kercher and slit her throat while he was in the bathroom. He says he tried to rescuscitate the dying girl, who managed to utter the sound “af” as a clue to her killer. Today, however, it emerged that Mr Guede had told his father, Roger, that there was another person at the scene of the crime.

“I want to return to Italy as soon as possible and tell what I know,” he told his father in his prison cell at Mannheim, according to Il Messaggero, the Rome daily. “I want to indicate who Meredith's murderer was. I saw him, I would recognise him again. He was not alone, there was someone else.” He did not say whether the other person was male or female.

He told his father, whom he had not seen for four years: “I swear it was not me. I was with Meredith, we kissed each other and went a bit further. Then I felt ill and went to the bathroom while listening to my iPod.” He repeated his earlier story, that he had heard Meredith scream and had emerged to find the unknown Italian with a knife in his hand; they grappled and he suffered a cut to his right hand.

He said he had heard the Italian say to the second person: “I found a Negro in there; they will think he's guilty.” He said that, at this, he had taken fright and fled. As he left the house he saw a small car leaving.

He said he thought he would recognise Ms Kercher's assailant even though the light had been dim, with the only lighting in the bedroom from Ms Kercher's bedside lamp. He said he had gone home and changed because there was blood on his shoes, and after wandering around for two days he had left Perugia “because I was afraid. I was in that house, and I didn't think anyone would believe me. I'm still afraid”.

He repeated that Ms Kercher had complained that €250 was missing from her bedside drawer and had accused Amanda Knox, her American flatmate, of stealing it to buy drugs. Ms Knox and Raffaele Sollecito, her Italian boyfriend, are in prison in Perugia, suspected of involvement in the sexual assault and murder.

The court in Perugia, which last Friday rejected appeals by Ms Knox and Mr Sollecito to be released today, said Ms Kercher had been killed by "those who knew her well" and that "more than one person" had taken part in the assault. Giving its reasons for sending the suspects back to jail, the court said the "hypothesis of an act of group violence" had been "reinforced" during the inquiry following Ms Kercher's death nearly five weeks ago.The ruling described Mr Sollecito as a young man with a fragile temperament who was impressionable and easily led. His version of events — that he spent the evening and night of the murder at his flat — was "unpardonably implausible".

The judges said they had concluded that Ms Knox and Mr Sollecito were together at 8.40 on the evening of November 1 and spent the night and the following morning together. The kitchen knife found at Mr Sollecito's flat was almost certainly the murder weapon, and had been cleaned with bleach in an attempt to wash off blood.

The court said Ms Knox was "without inhibitions" and could strike again if freed. "The role of Amanda cannot be secondary" the judges said. "She is a young woman with a multiform personality". She had a capacity for self dramatisation "which one might call fatal".

Mr Guede is expected to arrive at Rome airport from Germany tomorrow morning before being transferred to the prison in Perugia where Ms Knox and Mr Sollecito are being held.

Ms Knox initially accused Patrick Lumumba, another African immigrant in Perugia, of the murder, but later withdrew this. Mr Lumumba was questioned and released for lack of evidence. He was questioned again on Tuesday but exercised his right to remain silent, saying he had already given a full account of his movements to police that proved his innocence.

Mr Guede came to Perugia with his father at the age of 5. He speaks fluent Italian. His father returned to the Ivory Coast when he was a teenager and Mr Guede was taken in by a local family, who found him work. However, they severed relations with him after he was detained by police several times for minor drugs offences.

Times Recommends

• Tehran cannot live up to its rhetoric
• The new unicycle that will ‘change the world’
• We cannot wish away Iran’s bomb