Italian police named a fourth suspect Monday in connection to the brutal murder of British student Meredith Kercher in Perugia.

Rudy Hermann, 21, an immigrant from the Ivory Coast, is thought to have sexually assaulted Kercher after his DNA was found on the exchange student’s dead body.

Hermann was often seen at the whitewashed cottage where Kercher lived with her American roommate and murder suspect Amanda Knox and his fingerprints have been found on Kercher's bloodsoaked pillow and in the bathroom. Analysis of feces and toilet paper in the cottage bathroom also match his DNA.

Witnesses said that Hermann was seen in a street on the outskirts of Perugia three days ago. He may now have fled abroad or to Milan, because he knows the city well and has friends and relatives there with whom he could take refuge.

Giuliano Mignini, the chief investigating magistrate, has issued a warrant for Hermann’s arrest, and his photograph has been circulated to border police at ports and airports. However, one police source said: "We think he is still in Italy and may be not far away."

The Italian media has published photocopies of his Italian identity card, with the full name as Rudy Hermann Guede and police have also been circulating his photograph to bars and shops in Perugia.

Police said that Hermann had been "adopted" by a local family and worked in their agricultural business, but had fallen out with them over his "rebellious" behavior. Also known as "The Baron,” he had a history of drug dealing and violence, and had once been stabbed in the stomach during a fight in Perugia's main piazza.

Reports said that he has been in Italy since he was a child, and still has relatives at Lodi, near Milan. After his period in the agricultural business, he left Perugia for Milan, where he had been detained and questioned several times by police over drugs offenses.

He then returned to Perugia, where he continued to deal drugs among the many foreign students in the town. Friends of the dead girl have told police that he was often at the cottage that Kercher and Knox shared, and that on one occasion he was so drunk -- or drugged -- that he "fell asleep on the lavatory."

Reports said that Hermann was "athletic," and often played basketball on Piazza Grimana, the municipal square between the University for Foreigners and the cottage where Knox is alleged to have arranged to meet Diya "Patrick" Lumumba, the Congolese bar owner she accuses of the crime, on the evening of the murder.

Witnesses told police that Hermann disappeared shortly after the murder, telling friends "I'm going dancing in Milan." But some witnesses reported seeing him in a street on the outskirts of Perugia three days ago. Reports said that the hunt had spread to Europe and the name appeared on international warrants for his arrest.

Police reconstructing the killing now believe that Kercher was forced to kneel in front of a dresser in her bedroom as she was sexually assaulted and her throat was cut.

It had been previously assumed that Kercher was killed on the bed. However, Italian news reports Monday quoted police as saying that there was "unequivocal proof" from forensic science tests that the murder had taken place in front of the dresser, with Kercher on her knees.

Reports said that a quilt had been used not only to cover Kercher’s body but to drag it to where it was found on the floor between the bed and the bedroom door.

Police now believe that it is "psychologically significant" that Knox made a reference to the dresser when first questioned by police, claiming that when police broke down Kercher's locked bedroom door, Knox’s boyfriend, Raffaele Sollecito, told her he could see Meredith's body covered by a duvet "in the wardrobe."

Last week, police laboratory tests revealed that the DNA of Kercher was on the tip of a kitchen knife found at Sollecito’s flat, with Knox's DNA close to the handle. Police suspect that Sollecito and Knox attempted to clean blood from the knife, failing to realize that this would still leave identifiable DNA traces.

Police have seized a handbag belonging to Knox, which they believe may have been used to transport the kitchen knife from Mr Sollecito's flat and back again. They say this amounts to proof of "premeditated murder".