Amanda Knox, 20 years old, an honour student at the University of Washington, is being held as a murder suspect in an Italian jail.

This may be a case of a totally innocent girl wrongly accused and held. But some think it may be a case of a young girl, previously a studious, stay-at-home type, who lost all restraint in her new foreign environment.

In August 2007 Amanda went to study in Perugia in Italy. She shared a cottage with three women, one of whom was Meredith Kercher. One night in November Kercher was brutally murdered in her bedroom.. Amanda and her boyfriend were arrested as murder suspects. She has been protesting her innocence, which she writes in her diary.

She has maintained that she was out on the night of the murder, staying with her boyfriend, and on return to the cottage in the morning, found the front door was left open and that Kercher's room was locked.

However, during part of the questioning by the police she is said to have admitted to having a “vision” of being in the cottage during the attack on Kercher.

The police theory is that they were involved in some violent sex game during which Kercher was assaulted. And perhaps drugs were involved.

Another man who admitted to having been with Kercher, said he found her in the bedroom with her throat cut, and saw an intruder fleeing. He said neither Amanda nor her boyfriend was at the cottage.

Under Italian law, a suspect can be held for one year without being charged.

ABC has run a 20/20 program on her story.