US student grilled in Italy sex-murder trial

American student Amanda Knox weathered a second day of tough questioning yesterday over charges that she helped kill a British housemate who refused to join in a group sex session in Italy.

Prominent public prosecutor Giuliano Mignini grilled the 21-year-old exchange student accused of taking part in an orgy that turned violent with the stabbing death of Meredith Kercher, 22, of Britain.

In a testy exchange, Mignini questioned Knox's assertion that interrogators had extracted false statements from her by bullying her and calling her a "stupid liar".

She repeated the charge that a policewoman had twice hit her on the back of her head, which Italian police have strongly denied.

Mignini focused on Knox's assertions that her false statements - notably, that her part-time employer Patrick Lumumba was the killer - were the result of "suggestions" during aggressive police questioning.

Knox had said Friday that she was under duress when she stated that she was at home at the time of the murder and could hear Kercher's screams.

Instead, Knox said, she spent the night of November 1, 2007, with Sollecito at his flat, where they smoked marijuana, had sex and watched a film.

The two have been held since a few days after Kercher was found semi-nude with her throat cut in the house in the walled medieval town of Perugia that she shared with Knox.

Defence lawyer Carlo Dalla Vedova asked Knox about an element of the probe that initially seemed to seal the case for the prosecution: the discovery of a knife belonging to the American at Sollecito's flat.

In a wiretapped telephone call with her mother, she talked of her concern after learning about it while in custody.

"I was worried because for me it was impossible. I didn't know how it could be there," she said.

A third defendant in the case, 20-year-old Rudy Guede, from Ivory Coast, has already been convicted and sentenced to 30 years for his role in the murder.

While claiming innocence, Guede, who worked as a casual labourer here, opted for a so-called 'fast-track' trial limited to evidence from the probe.

In the prosecutors' scenario, Guede held Kercher down while Sollecito and Knox stabbed her.

The Congolese Lumumba, who was held for two weeks before being released without charge, is suing Knox for defamation and was present at the hearing.

Kercher's family are seeking €30m from the alleged killers.

Later yesterday, the defence summoned its first character witness on Knox's behalf, a university classmate in her native Seattle, Washington, who lived in the same dormitory.

Describing himself as Knox's "best friend" but not her boyfriend, Andrew Seliber, 22, said he attended a party described in sensational terms by the British newspaper The Daily Mail's online edition, Mail Online.

Under the headline 'The wild, raunchy past of Foxy Knoxy', the article said students "high on drink and drugs, were hurling rocks into the road" outside.

The article quoted a guest as saying the party was a scene of debauchery, "with drink, drugs and bodies everywhere. Everyone just wanted to get drunk, get high and get laid. There was also a lot of violence because everyone was so pumped up."

"The article said a lot of things that didn't happen at the party," Seliber said.

Knox was like "any other college student" in that she drank alcohol and smoked marijuana occasionally, he said, adding: "She cares a lot about her body."