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.

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.

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.

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.