Meredith suspect caught on CCTV at murder scene

The American university student at the heart of the police inquiry into the death of Meredith Kercher was caught on camera entering the building where the murder took place on the evening of the killing, it emerged yesterday.

Police revealed that Amanda Knox was picked up by CCTV cameras situated above the building where she lived with the Leeds University student, contradicting her previous claims that she had spent the night with her Italian boyfriend Raffaele Sollecito.

Since her arrest 10 days ago, Ms Knox has repeatedly changed the story of where she was on the night of the murder, and officers investigating the killing are said to be hopeful that seeing the footage will force her to confess to being at the scene of the crime.

The images appear to show Ms Knox wearing a light coloured skirt and top entering the building at 8.43pm on 1 November, the night Ms Kercher was killed. The 21-year-old student from Surrey had been studying in the Italian town of Perugia on a one-year Erasmus programme. She was found with her throat cut on the morning of 2 November in the villa she shared with Ms Knox and two female Italian students.

Ms Knox, her boyfriend and a third man, Congolese musician and local barman Patrick Lumumba, are accused of manslaughter and sexual violence but have yet to be charged by Italian police, who have been given the authority to hold the suspects for up to a year while the investigation continues. All three deny any involvement in the killing.

The existence of the camera footage will seriously undermine Ms Knox's alibi that she spent the evening at her boyfriend's house. It was her second version of what happened that night, when during a pre-dawn interrogation she admitted being in the house and hearing Meredith scream, that prompted police to claim the case was "closed". But following a visit by her mother to the prison where she is being held, Ms Knox has reverted once again to her original testimony.

According to Italian newspapers yesterday, Mr Lumumba's testimony has also taken a knock following the questioning of a Swiss professor who Mr Lumumba claimed would provide him with an alibi. The bar owner said the professor was drinking in Le Chic from 8pm to 10pm and would be able to confirm Mr Lumumba's presence there. But police investigators, who questioned the Swiss national in secrecy away from the media glare after he flew into Italy on Sunday, have revealed that he could not confirm that the Congolese national was present the whole time. Police claim that at 8.38pm Mr Lumumba's mobile phone placed him in the vicinity of Ms Kercher's house. Last week a leak from the forensic scientists investigating the crime revealed that none of the 140 finger and palm prints inside the room belong to Mr Lumumba.

The camera footage incriminating Ms Knox also throws up as many questions as it answers. Doubts were raised yesterday over why, if the CCTV camera caught Ms Knox entering the cottage that night, the two other suspects were not also filmed.

According to Corriere della Serra, the police believe Ms Knox showed up because she was wearing light clothing and that anyone entering at night wearing dark clothes would be missed by the cameras.

There were also reports yesterday that police may be looking for a further female suspect after a heel print was found that did not match any of the house's inhabitants. Police are already looking for another man of North African origin.

The three people in the frame

* Amanda Knox

Investigators believe that the student from Seattle holds the key to what happened on the night of Meredith Kercher's murder. She implicated Patrick Lumumba following her arrest but has changed her testimony at least three times. At one point she admitted to being in the house and of hearing Ms Kercher's screams from the kitchen but has since told her mother that she was "confused" when she said this and in fact was away from the house the whole night. Police claim she is a pathological liar.

* Raffaele Sollecito

The son of a wealthy urologist claims he spent the night of the murder with Ms Knox, his girlfriend of two weeks, at his house and only discovered that something strange had happened the following morning when Ms Knox returned to shower. He claims to have been smoking dope and surfing the Net alone at home, and to have received a phone call from his father on his flat's landline numberlate in the evening. But police investigations have so far failed to find any evidence of the call.

* Patrick Lumumba

The Congolese musician and bar owner, a well known figure on Perugia's student scene, has been most strongly implicated in Ms Kercher's murder by Ms Knox's testimony. He claims to have spent the night at the bar he owns in the centre of town, and his lawyer has said he can produce 20 witnesses who can place him away from the crime. Mobile phone records, however, place him near the whitewashed cottage on the evening Ms Kercher died.