Murder Suspect's Dad Slams American Coed

The father of a 24-year-old Italian man held as one of three suspects in the brutal slaying of a British exchange student in Italy told ABC News that his son's life has been ruined by his American girlfriend — another suspect in the case whose DNA may now link her to a murder weapon.

Lawyers for Raffaele Sollecito, 24, announced Thursday that traces of DNA from Seattle exchange student Amanda Knox, Sollecito's girlfriend, were discovered on a kitchen knife that may have been used to kill Knox's roommate in their Perugia, Italy, apartment.

Police seized the knife from Sollecito's house, his attorneys and family said in a written statement released Thursday night. According to the statement, DNA from Knox, as well as victim Meredith Kercher, was detected on the knife. Sollecito's DNA was not found on the knife, according to the statement. There was no DNA tying Sollecito to the weapon.

Sollecito's lawyer said that Knox was often at his client's house, so it was no surprise that her DNA would be found on the knife. The presence of Kercher's DNA remained a mystery, he said.

The Italian newspaper Corriere della Sera reported that Kercher's DNA was found on the tip of the knife, while Knox's was on the handle of the blade, which was described as more than six inches long. Additional forensics tests were planned for Sollecito's apartment today.

In an off-camera interview with ABC News, Sollecito's father, Francesco Sollecito, blamed Knox for the entire situation.

"She has ruined my son's life," Sollecito's father said. "I damn the day he met her."

Sollecito, 20-year-old Knox and 38-year-old Congolese bar owner Diya "Patrick" Lumumba remain jailed on the suspicion of killing Kercher.

Knox's attorney was not available for comment today, but her mother said earlier this week that her daughter maintains her innocence in the crime.

"She's sure that as the investigation continues, the truth will come out and she'll be proven innocent," Edda Mellas said.

Police have said that Kercher died after she was stabbed in the neck while trying to fight off a sexual attack. The three suspects have been detained since Nov. 6, but no charges have been filed.

The defense lawyers for each of the three detained in the murder have until Saturday to request a review of the case. Under Italian law, once the request is made, the prosecutor has five days to present evidence. Then, a new set of three judges have up to 10 days to meet, examine the evidence and decide whether those detained should be released.

Knox reportedly has changed her version of events several times, at one point accusing the Congolese suspect in the slaying.

Prison chaplain the Rev. Saulo Scarabattoli has visited regularly with Knox since she was jailed. Asked whether Knox could be capable of such a brutal crime, Scarabattoli said he was unsure.

"I don't want to believe it," he said. "But it's true that anyone can lose control."

Information from The Associated Press was used in this report.