CHICAGO (CBS) — Letters sent to a former attorney for convicted killer Drew Peterson have raised questions about whether Peterson was set up on charges he sought to have a prosecutor killed.

Peterson has been charged with solicitation of murder, for allegedly trying to hire a hitman to kill Will County State’s Attorney James Glasgow, who led the prosecution that sent Peterson to prison for murder.

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The allegation Peterson was set up by two inmates at Menard Correctional Center came in two letters another inmate sent to his former attorney, Joel Brodsky.

While Brodsky was not commenting, and WBBM has not seen the letters; but according to information received by WBBM, the inmate claimed there was a plot to entrap Peterson, and the other inmates were not acting on their own.

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According to the letters, two inmates involved in the alleged plot were acting at the direction of someone else, and one was placed at the prison specifically to set up Peterson.

Peterson has been sentenced to 38 years for the murder of his third wife, Kathleen Savio. He’s also a suspect in the disappearance of his fourth wife, Stacy Peterson.

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The former Bolingbrook police sergeant has appealed his murder conviction.