Perugia, Italy ? An American student has accused a Congolese pub owner of knifing her British roommate to death, saying she covered her ears to drown out the screams, according to a judge’s ruling Friday ordering the woman, her Italian boyfriend and the pub owner kept in jail.

The judge said Amanda Marie Knox, of Seattle, was hazy about the events from smoking hashish before the slaying and that the murder weapon was a knife that belonged to Knox’s boyfriend.

Knox, 20, Raffaele Sollecito, 23, and Diya “Patrick” Lumumba, 38, have been detained since Tuesday as suspects in the sexual assault and killing of Meredith Kercher, 21, who was found dead Nov. 2. All three deny involvement in the death, their attorneys say.

No charges have been filed, but Judge Claudia Matteini ruled there were “serious indications of guilt” that warranted keeping the three in jail for up to a year while the investigation continues.

The 19-page ruling said that Knox, in her meetings with prosecutors, accused Lumumba of killing Kercher.

Knox has “confused memories, since she had taken hashish in the afternoon,” the ruling read. But it said she told prosecutors Lumumba “had a crush” on her roommate and he and the victim had gone into a bedroom to have sex.

“She added that she could not remember if (Meredith) had been previously threatened but that it was Patrick who killed her,” the ruling read. “She made clear that in those moments … she heard Meredith scream so much that she, being scared, covered her ears.”

An attorney for Knox, Luciano Ghirga, told reporters Friday that his client had given “three versions and … it is difficult to evaluate which one is true.”

He also said he had warned Knox against making unfounded accusations. “We told her that it would be worse than assassination to accuse an innocent person. We explained to her what slander means in Italy and we’ll see,” Ghirga said.

Lumumba’s attorney, Carlo Pacelli, maintains his client was at his pub and accuses Knox of making “slanderous statements.”

“She repeatedly changes her story,” he said Thursday.

One of Sollecito’s attorneys, Tiziano Tedeschi, previously told reporters his client “wasn’t at the crime scene.”

Under Italian law, suspects can be held without charge if a judge rules there is enough evidence to jail them and there is a chance they might flee, repeat the crime or tamper with evidence. Prosecutors may later seek to indict the suspects and put them on trial.

The judge said in her ruling that the suspects might try to flee Italy if released.

Kercher’s body was found in the apartment she shared with Knox, and police said she died fighting off a sexual attack. The coroner said Kercher was stabbed in the neck.

The judge said it was not yet clear who inflicted the fatal wound, but her ruling said Sollecito’s footprints were found in Kercher’s room and identified the murder weapon as a knife with a 3.3-inch-long blade that the Italian usually had with him.

In her reconstruction of the incident, the judge said Knox, who worked for Lumumba at his Perugia bar, let the two men into the apartment with her keys.

“Then something went wrong,” Matteini wrote. “The two (men) demanded some kind of sexual act, which (Kercher) refused to do. She was then threatened with a knife, which Sollecito always carried with him, and with which Meredith was stabbed in the neck.”