Meredith: Fourth arrest hinted

Reports from Italy said an order for his capture was in place. Newspaper La Repubblica said the man was thought to be of African origin, perhaps from the Ivory Coast, and may be linked to the world of drugs. Investigators have become convinced they should seek a fourth person after finding a bloody fingerprint on a pillow in the flat where the 21-year-old was killed, and another on toilet paper, which do not match the three people in custody.

Miss Kercher's American flatmate Amanda Knox, 20, Knox's Italian boyfriend Raffaele Sollecito, 23, and Congolese bar owner Diya "Patrick" Lumumba, 38, are all ordered held in custody for up to a year while police continue their investigations into the murder in Perugia, central Italy. They are suspected of sexually assaulting and then killing the Leeds University exchange student from Coulsdon, Surrey, whose body was found on November 2. Prosecutors believe she was murdered after refusing to take part in an extreme sex game. The three suspects all deny any involvement in her death.

Knox has told investigators that Lumumba was infatuated with Miss Kercher and was in the British woman's bedroom in the hours before the victim was killed, but Lumumba has denied being in the house.

One of Lumumba's lawyers, Carlo Pacelli, told reporters the defence was seeking further scientific analysis to better establish how and precisely when Miss Kercher was killed, including a possible new post-mortem examination on the body, which was flown to Britain last Sunday.

Based on the post-mortem examination by the Perugia coroner and accounts by Miss Kercher's friends of when she ate dinner with them on November 1, it is believed she died between 9pm and 11pm on that date. However if it could be shown that the time of death was later, that could help Lumumba, who has claimed he was in the pub later in the evening.

Meanwhile Miss Kercher's Italian boyfriend has said Knox was "cool and calm" when he saw her at the police station after the killing.

Giacomo Silenzi, 22, who had been dating Meredith for just 10 days, told the Mail on Sunday: "I had a cast-iron alibi because I had been at my parents' house since the Monday - it was a bank holiday in Italy."

He was taken to a waiting room and Knox was there.

"I couldn't help thinking how cool and calm Amanda was. Meredith's other English friends were devastated and I was upset, but Amanda was as cool as anything and completely emotionless. Her eyes didn't seem to show any sadness and I remember wondering if she could have been involved."