Italy police hunt 4th murder suspect

ROME, Italy (CNN) -- Investigators probing the killing of a 21-year-old British woman in Italy say they have identified a new suspect in the case after discovering a bloody fingerprint on a pillow at the scene of the crime.

The body of Meredith Kercher was found half-naked with a stab wound to the neck on November 2 at her home in Perugia, where she was studying as an exchange student at the city's university.

A report issued by an Italian judge last week suggested that the British student may have been sexually assaulted at knife point before she was killed in her bed.

Amanda Knox, Kercher's 20-year-old American roommate; Knox's Italian boyfriend, Raffaele Sollecito, 23; and her Congolese boss, bar owner Patrick Lumumba, 38, are being held in connection with the death.

An Italian police source told CNN Sunday that investigators were searching for a fourth suspect who had been identified through a fingerprint found on a blood stain on a pillow inside Kercher's villa.

The police source refused to confirm if the suspect had a criminal record, although the source said it was "very possible" the suspect was a man. He said police were awaiting the results of further forensic tests. Watch investigators at scene of killing »

All three suspects deny any involvement in the killing.

Knox, from Seattle, told police Lumumba was responsible for Kercher's death. She later retracted that statement via her mother, saying drugs rendered her account of that night "confused."

She has given investigators three different versions of what occurred. On Friday, her lawyer said even he was having trouble discerning the truth.

DNA belonging to both Kercher and Knox was found on Thursday on a knife belonging to Sollecito at the Italian's apartment, police said.

Kercher's DNA was found near the tip of the knife, while Knox's DNA was discovered near the base. Police also found the knife had been washed, authorities said.

A report issued last week by an Italian judge paints a disturbing picture of how Kercher is believed to have died.

"The fact that Meredith was a victim of violence is evidence from the state in which her body was found," said the report issued by Judge Claudia Matteini of the Civil and Penal Tribunal of Perugia, according to a translation posted on The London Times' Web site.

The judge's report said a pathologist had found bruising and lesions to Kercher's neck that suggested the victim had been held down with a knife pushed to her throat.

The report added that "bruises indicate a sexual act carried out or attempted in a hurry or against the girl's wishes."

According to the report, Sollecito and Knox spent the afternoon of November 1 smoking hashish before meeting up with Lumumba. The three then went to the villa that the American student shared with Kercher, the report went on.

At some point in the evening Kercher went into her bedroom with Lumumba, but "something went wrong," the judge wrote. Matteini said the three suspects then staged a break-in in an attempt to cover their tracks. E-mail to a friend

-- CNN's Hada Messia and Jennifer Eccleston contributed to this report