Rome, Italy (CNN) -- A jailed Italian mobster claims he can prove American student Amanda Knox, her former boyfriend and a drifter are innocent of murdering Knox's British roommate because he knows who the real killer is -- his brother. Luciano Aviello, 41, made the statement during a videotaped interview with Knox's lawyers. He said he had tried to write the Italian court several times to say that Knox and the others were innocent, but no one ever contacted him, defense and prosecution officials said. A source close to the case tells CNN that Aviello, who has been in and out of prison since age 17, was out of prison, living down the street from Knox and Meredith Kercher and under a "protection program" at the time of the murder. Aviello is serving 17 years in an Italian prison because of his association with the Camorra crime family. According to Italian media reports and Britain's Daily Mail, he has testified against the mob at several trials, always from behind a screen to shield his identity.
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Luciano Aviello says his brother told him he killed Meredith Kercher in botched robbery
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Aviello says he buried brother's bloody knife, clothes and keys to Kercher's apartment
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Amanda Knox's lawyers want Aviello's story investigated for her appeal
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Knox, her former boyfriend were convicted of murdering Kercher in December 2009
"There's no motivation I would guess for the police to actually pursue it," he said, when asked if the keys, clothing or knife @placeholder claims were buried were ever dug up.