Two key suspects held over the murder in Perugia of the British exchange student Meredith Kercher have lost their appeal to be freed from jail.

A court in the Italian town ruled yesterday that Amanda Knox and her Italian boyfriend, Raffaele Sollecito, must remain in Capanne prison, where they were remanded on November 9.

Ms Kercher, a 21-year-old student from Leeds University, was found murdered at the house she shared with Ms Knox a week earlier. Her throat had been slit and police said that there was evidence of sexual violence.

Ms Knox, 20, an American, and Mr Sollecito, 23, told a court reviewing their case that they had played no part in the killing and appealed to be released while police continued their investigations.

But legal sources said that Massimo Ricciarelli, the review judge, accepted the prosecution argument that the investigation so far suggested that “on the evening and night of November 1 Ms Knox and Mr Sollecito played an active role and afterwards sought to erase the traces of the murder”.

The judge also agreed that the pair must remain in prison to ensure that they did not either flee the country or seek to interfere with evidence.

Amid dramatic scenes in court, Ms Knox broke down in tears as she insisted that she was not at the Perugia cottage when Ms Kercher had her throat cut. Speaking in English, she told Mr Ricciarelli: “I am innocent, I was at Raffaele’s house the whole time. I want to tell the truth.”

Ms Knox, from the University of Washington, and Mr Sollecito have not seen each other since they were arrested shortly after Ms Kercher’s body was found. They appeared in the same Perugia courthouse but arrived in separate police vans and did not meet, lawyers said.

Ms Knox also told the judge that she was sorry for the trouble that she had caused Diya “Patrick” Lumumba, a Congolese bar owner for whom she worked part time, by falsely claiming that he had had sex with Ms Kercher before murdering her. “I am sorry for Patrick and for the whole situation,” she said.

Both Mr Sollecito and Ms Knox deny that they were at the house when the murder took place.

Giuliano Mignini, the chief prosecutor, said that blood on a tap in the bathroom of the house belonged to Ms Knox and that proved she was there on the night of the murder.

But Luciano Ghirga, Ms Knox’s lawyer, argued that a statement that she made early in the inquiry, admitting that she was at the house, was made under duress without a lawyer present. He produced expert witnesses to try to prove that a kitchen knife with Ms Knox’s DNA on it was not the murder weapon, as police claim.

Mr Sollecito’s lawyers, Marco Brusco and Luca Maori, also contested evidence against their client, saying that the footprint found in Ms Kercher’s blood did not match his Nike trainers as police allege. They produced computer experts in an attempt to disprove the police’s contention that Mr Sollecito’s computer was not connected to the internet at his flat on the night of the murder as he maintains.

Francesco Maresca, the lawyer representing the Kercher family, said that he was very satisfied with yesterday’s decision and that the family had been informed.

Another man, Rudy Hermann Guede, who was arrested in connection with the murder on November 20 and is awaiting extradition from Germany, has told German police and his lawyers that he was at the house and had sex with Ms Kercher on the night she died.

But the Ivory Coast immigrant, who has joint Italian nationality, maintains the sex was consensual and that the “real killer” was an Italian whom he did not know.

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