A prison inmate whom Drew Peterson allegedly enlisted to kill a state's attorney says the former suburban Chicago police officer also admitted killing his missing fourth wife. The Chicago Tribune reports that Antonio Smith testified Monday that the ex-Bolingbrook sergeant referred to Stacey Peterson as a "dead woman" while discussing how to kill Will County State's Attorney James Glasgow. Peterson has never been charged in Stacey Peterson's disappearance and has maintained his innocence. He's serving a 38-year sentence in the 2004 death of ex-wife Kathleen Savio in a case that was reopened after Stacey Peterson went missing in 2007. Peterson has pleaded not guilty in the current case and faces an additional 60 years in prison.