CHICAGO (CBS) — Convicted killer Drew Peterson has been transferred out of federal prison.

Peterson was transferred to a medium-security prison in Terre Haute, Indiana back in 2017. Before that, he had been serving his sentence at the Menard Correctional Center in southern Illinois.

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Late Monday afternoon, CBS 2 learned that Peterson is now at a state facility outside of Illinois. It is not clear why he was moved.

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In 2013, Peterson – a former Bolingbrook police sergeant – was sentenced to 38 years in prison for the murder of his third wife, Kathleen Savio. While in prison for that crime, he was convicted of trying to hire a fellow inmate to kill Will County State’s Attorney James Glasgow, and was sentenced to an additional 40 years in prison.

Peterson has been named a suspect in the disappearance of his fourth wife, Stacy Peterson, in 2007, but has not been charged in that case.

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As authorities were investigating Stacy’s case, they also reopened the investigation into Savio’s death, which originally was ruled an accidental drowning. A new autopsy later ruled Savio’s death a homicide, and Peterson was convicted of her murder.