A a photograph of Rudy Hermann Guede shows him standing next to the fashion designer Giorgio Armani. Taken at the Armani Bar, where the designer sometimes poses with tourists, it shows the Rudy many foreign students in Perugia got to know in the town’s bars, pubs and discos: a tall, athletic African immigrant with an engaging manner and a love of basketball and night life.

Stefano Bonassi, one of four Italian students who lived in the flat below the cottage where the murderous assault on Meredith Kercher took place, says he remembers Mr Guede as a “tall, thin guy who always wore basketball shoes and baggy trousers. His nickname was Body Roga”.

But there was another Rudy, the small-time drug dealer and drifter with a record of petty crime who according to some witnesses harassed women and stole from their handbags. Shortly before Kercher’s murder he was detained in Milan for an alleged theft. He had broken into a school to hide from police and had a knife in his hand.

Rudy hardly had the best start in life: he was born in the Ivory Coast, his mother left the family and he was brought up by his father, Pacome Roger Guede, who left Abidjan for Italy and found work in Perugia as a building labourer in the early 1990s. They settled at Ponte San Giovanni, a suburb of Perugia, and at the age of 5 Rudy went to the local primary school.

With no mother to look after him, Rudy was often taken home by his teachers when school ended until his father came back from work. When Rudy was 16 his father returned to Africa, saying he would be back in three months. Instead the teenager was taken in and informally adopted by Paolo Caporali, 63, a wealthy local businessman whose company sponsored the local basketball team for which Rudy played. The boy was a natural and played for the Perugia youth team in the 2004-05 season.

At first Mr Caporali had high hopes of the young immigrant, who seemed to have integrated well, spoke fluent Italian with a local Umbrian accent, and acquired joint Italian nationality. For a while he sporadically studied accountancy and hotelkeeping.

But drugs, sex and nightlife held more attractions. Rudy spent more and more time in the big city life of Milan (an aunt lived in nearby Lecco), working in bars, but he returned now and then to Perugia to mingle with the 36,000-strong student community — and allegedly to introduce students from middle-class families to drugs.

Even when Rudy left for Milan Mr Caporali’s family offered him a job as a gardener at a farmhouse bed and breakfast that it owned. He hardly ever turned up for work, and in August — the month Amanda Knox and Meredith Kercher arrived in Perugia from Seattle and Coulsdon and set up house together — he was sacked.

He posted photographs of himself on his Facebook site claiming to be an extraterrestrial and making grotesque faces with the message: “Love is the only solution, enough of war, enough of killing, enough of racism, enough of hating our brothers”. But he also wrote: “I am Dracula, I will drink your blood.”

“He was like another son to us,” Mr Caporali said. “I cannot hide the fact that he disappointed me. I thought I could help him to build a future, but with the passing of time I realised I had made a mistake.”

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