Amanda Knox, the American student accused of murdering Meredith Kercher, covered her face with her hands yesterday as police footage of the murder scene was shown in court.

As the police video began, showing the outside of the cottage in Perugia that she had shared with Ms Kercher, Ms Knox exchanged grins with Raffaele Sollecito, her co-accused and former boyfriend, and mouthed a message to him.

The camera moved into Ms Kercher’s bedroom, showing her bloodied face with eyes open and a foot sticking out from a duvet on the bloodstained floor. At this point Ms Knox looked away frowning, then put her hands over her face, occasionally peeping through her fingers at the screen. Mr Sollecito continued to stare at the footage with no expression.

Ms Kercher, 20, from Coulsdon, Surrey, was in Italy as part of a year-long exchange programme with the University of Leeds. She had been in Perugia for only two months when she was killed.

She was found semi-naked and with her throat cut after refusing to take part in a drug-fuelled sex game, according to the prosecution.

Ms Knox, 21, from Seattle, and Mr Sollecito, 25, from Bari in southern Italy, have denied murder and sexual assault.

The police footage showed forensic scientists examining bloody footprints and fingerprints, and a handprint in blood on the bedroom wall, which was later identified as that of Rudy Guede, the Ivory Coast immigrant who was sentenced to 30 years in prison in October for the crime.

The film showed a large stone under a desk in the bedroom of Filomena Romanelli, one of two Italian women who also lived in the cottage. The defence said that the stone, which was used to break a window, is proof that Ms Kercher was killed by a lone burglar. The prosecution said that Ms Knox and Mr Sollecito broke the window in an attempt to simulate a break-in.

Alberto Intini, the head of the Italian police forensic science unit, told the court that a Nike trainer shoeprint in blood was compatible with shoes owned by Mr Sollecito. When he was cross-questioned by the defence he agreed that the print was compatible with shoes owned by Mr Guede.

Forensic scientists said that only one of Ms Knox’s fingerprints — on a glass in the kitchen — was found at the cottage even though she lived there. Giuliano Mignini, the prosecutor, said this was because the cottage had been cleaned after the murder.

Mr Intini said that persistent allegations by defence lawyers that forensic evidence from the murder scene had been contaminated because objects such as the mattress and wardrobe doors had been moved between the first inspection of the cottage on November 2, 2007 and the second on December 18, were misplaced because moving objects was normal practice.

The trial continues.

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