A second 'Prisoner X' was being held in top-secret conditions in the same jail where an Israeli-Australian spy took his his own life in 2010, a newspaper reported on Tuesday.
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Haaretz said the second prisoner was being held in Block 13 and that like Zygier, his case was being handled by the Shin Bet internal security service and the prison's intelligence officers.
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Avigdor Feldman, a lawyer who visited Zygier just days before his death and who specialises in security cases, told army radio that certain assumptions could be drawn from a detainee being classified as 'prisoner X.'

"They are Israeli, they work in institutions linked to security whose activities are shrouded in secrecy," he said.

"And their detention demonstrates the failure of these organisations which are not capable of preventing offences such as those for which these agents have been arrested," he said.