PERUGIA IS one of those places where the quality of provincial life in Italy is seen at its best. A mediaeval town clinging to an Umbrian hillside, its treasures of art and architecture draw thousands of tourists every year. And in recent times its wealth, dynamism and cosmopolitan spirit have been boosted by a popular University for Foreigners, offering a unique cultural experience to students from around the globe.

Amanda Knox, a 20-year-old American, was certainly captivated by its magic. "I've made plenty of friends here, and I have a lot of fun. I'm actually at one of my most happiest places right now, " she gushed, in a message posted on MySpace.com on October 15. Two weeks later, on the night after Hallowe'en, Perugia's magic would turn to ashes for the fresh-faced, innocent-looking young blonde from Seattle.

The reassuringly safe and civilised city proved fatal to her friend and flatmate, Meredith Kercher, a lively 21-year-old from Coulsdon, south London, who was studying in the city as part of the Erasmus student-exchange programme. Meredith was preparing to return to London to celebrate her mother's birthday with a suitcase full of Perugia's famous chocolates - of which, she confessed in an entry on Facebook, she had recently been eating too much.

Instead, she was found lying on the floor of her locked bedroom with her throat cut, one foot sticking out from under a duvet and blood soaking her pillow. Even more shocking, her friend Amanda was last week arrested as an alleged accomplice in her rape and murder.

On Friday, Judge Claudia Matteini ordered Knox and two male suspects to be remanded in prison for a year. In a 19-page document explaining her decision, the judge said Kercher had been killed after refusing the sexual advances of the other two suspects, 44-year-old Congolese musician and bar manager Patrick Diya Lumumba and Knox's Italian boyfriend Raffaele Sollecito, 23, who was also studying in Perugia.

According to the police reconstruction of events on the night of November 1, Knox was present at the time of the murder and did nothing to protect her friend, subsequently lied to police about what happened and attempted to confuse investigators by staging a fake burglary. In the worst scenario, investigators said, she may actually have held her friend down while she was being raped.

In a harrowing testimony published by the respected Corriere Della Sera newspaper, Knox described how she blocked her ears in terror as she listened to thuds of violence and her friend's screams from a neighbouring room. According to this version, it was Lumumba who killed Meredith. But rather than doing anything about the attack, Knox, who said she had been smoking hashish, simply left for her boyfriend's flat, waking up in his bed the following morning.

Even this partial and far from convincing confession was produced with difficulty. "Knox repeatedly covers her face with her hands and shakes her head," police noted at the end of her traumatic testimony.

Her boyfriend, Sollecito, has been tied to the crime by physical evidence, according to Judge Matteini's report: Nike sneakers compatible with marks left in the blood on Meredith Kercher's floor and a flick-knife compatible with the wound that caused her death. Sollecito told investigators that he had carried a knife since the age of 13, using it as a fashion accessory that he changed when he changed his clothes. Both men deny being present in the house when Meredith died, and so far no physical evidence has been found that would place Lumumba, a popular and respected figure in Perugia, at the scene of the crime.

T he murder in the privileged international set of Perugia's foreign students, with its morbid sexual motive, has gripped the Italian media just as much as the British, focusing a spotlight on the once quiet city's modern ills of alcohol, drugs and promiscuous sex. It is also one of the first judicial cases in Italy in which the characters of the protagonists have been illuminated by their writings on social networking websites.

Many newspapers published photographs of Meredith (Mez to family and friends) dressed as a vampire for Hallowe'en, with fake blood running from her lips. Posted on her Facebook entry the day before her death, they showed a carefree, happy and attractive brunette having fun and constituted a shockingly macabre coincidence the day after.

The internet offered an insight into the character of Sollecito, an information technology student from southern Italy, seen in television pictures as he nervously caressed and comforted Knox outside what has been dubbed the house of horrors.

"I am very honest, peaceful, kind, but sometimes completely mad," he wrote in a blog on wayn.com, where his professed desire for "strong emotions capable of surprising you" took on a sinister aspect in the light of what was to follow. In humorous photos posted on another site, he appears as a mummy, or perhaps a surgeon, swathed in toilet paper and clutching a large cleaver - another bitter irony now that he is accused of murder.

But the fullest picture to emerge from internet is that of Amanda Knox, or Foxy Knoxy, as she signed herself in her MySpace blog. The light-hearted banter takes on a new dimension in relation to her current predicament. It reveals that she had given up a job as a trainee at the German parliament in Berlin because she was not being given enough to do, causing embarrassment to the influential uncle who had fixed it for her.

And it describes her meeting a skinny girl with a room to rent in Perugia. "It's a cute house that is right in the middle of this random garden in the middle of Perugia. Around us are apartment buildings, but we enter through a gate and there it is. I'm in love," Foxy Knoxy wrote.

In a later post, a handyman comes to fix the washing machine and ends up staying the night. Foxy bumps into him in his underwear in the morning, and bursts out laughing. "Not because he's scrawny or anything, but because Laura Mezzetti, another flatmate had been complaining a couple days previously that she hadn't gotten laid in a long time. Forza Laura!"

The blog reveals Foxy had been working at night in a bar called Le Chic. "It's a really small place owned by this man from the Congo. His name is Patrick."

Besides the personal reminiscences there are short stories. Particularly striking, under the circumstances, is one in which two brothers fight because one had drugged and raped a woman. One character, Kyle, tries to laugh off the accusation: "A thing you have to know about chicks is that they don't know what they want ... You have to show it to them."' Testimony about the private lives of members of the Perugia household, particularly in relation to sex and drugs, inevitably looms large in the murder investigation, and has been published at length in Italian newspapers. Though it creates the impression that Meredith may have found herself in a sexually licentious environment that made her feel ill at ease, it is unlikely in itself to solve the murder. That will almost certainly depend on forensic science and the thoroughness and technical competence of the Italian forensic experts.