Convicted murderer Drew Peterson is no longer an Illinois inmate.
The former Bolingbrook police sergeant serving time for killing his third wife has been transferred to federal custody.
The Stateville Northern Reception and Classification Center confirmed Tuesday afternoon that Peterson had moved to its facility in Joliet. Soon after, the Federal Bureau of Prisons confirmed to NBC 5 Investigates that Peterson was being housed at the federal penitentiary in Terre Haute, Indiana -- the same institution which once housed former Gov. George Ryan and the site where Oklahoma City bomber Tim McVeigh was put to death.
An Illinois Department of Corrections spokesperson said Peterson had been "transferred out of IDOC custody." His status on the facility's website was listed as "out of custody."
It remains unclear why Peterson was suddenly transferred. Both the Chicago office of the FBI and the United State's Attorney's office said they had nothing to do with taking him into federal custody.
The Illinois Department of Corrections said Peterson was transferred under provisions of a law called the Interstate Compact Agreement, which allows state and federal government to send and receive offenders.
"For safety and security purposes, the IDOC does not discuss the details concerning the placement of offenders who are transferred," the spoksperson told NBC 5.
Peterson, who was convicted of killing his third wife Kathleen Savio, and is suspected in the disappearance of his fourth wife Stacy Peterson, had been serving a 38-year sentence. The former Bolingbrook police sergeant was recently sentenced to another 40 years in prison after being convicted of a murder-for-hire scheme that involved trying to have the prosecutor who first put him in jail killed.
Peterson’s fourth wife, Stacy, vanished in 2007, and that set in motion the events that led to his 2012 conviction for Savio’s murder.
No one has ever been charged in connection with Stacy Peterson’s disappearance. However, Peterson, 63, remains the prime suspect, and Will County State’s Attorney James Glasgow told reporters last May “we never stop reviewing that case.”