A Congolese bar owner arrested in Italy over the murder of Coulsdon student Meredith Kercher has been released, Italian media reports say.

News agency Ansa said Diya Patrick Lumumba has been released from prison in Rome, two weeks after he was remanded in custody by a judge.

Three others - Meredith's housemate American student Amanda Knox, 20, her Italian boyfriend Raffaele Sollecito, 24, and Ivory Coast national Rudy Hermann Guede, 21- all remain in police custody.

Meredith was found semi-naked with her throat cut in her bedroom in Perugia on November 2 where she was on a university student exchange programme.

Guede was arrested by Interpol in Mainz, Germany, by police acting on an international arrest warrant after officers found a bloody fingerprint on a cushion in Meredith's home that did not match the suspects then held by police.

Detectives narrowed their search to the German city after spotting a message sent from his Facebook account.

Police traced him through the IP address of the computer he was using.

In the message, reportedly to a national newspaper, Guede said he knew he was the target of an international manhunt.

He faces charges of murder and sexual assault.

Police chief Arturo De Felice said the suspects were present at the murder scene and all played a different role.

According to the Perugia coroner, Meredith was found partially clothed under a duvet and her throat was cut with a pocket knife or a sharp piece of glass.

Mr De Felice told a press conference she was murdered fighting off a violent sexual attack and had been a "victim and nothing more".

Prosecutors say Meredith was killed after refusing to take part in an extreme sex game.