Stephen Peterson, son of convicted murderer and former police sergeant Drew Peterson, has come to believe his dad is guilty of more than killing Wife No. 3, for which he's been sentenced to 38 years in prison. He also thinks his father killed his fourth wife, and said so on a Lifetime show in January and again to the Chicago Tribune this month. "I don't want to come out and say he did it ... but, I'm sure he did it," Stephen now says. Since his father's conviction in 2012 for the 2004 killing of Kathleen Savio, his third wife, Stephen has lived in his father's home and raised his dad's kids. He has his suspicions about the 2007 disappearance of Stacy Peterson, in which his father remains a suspect. Stephen says that at first he believed his dad's stories that Savio drowned accidentally and that Stacy left him for another man—even though, Stephen says, the day after Stacy went missing his father brought over his guns and more than $200,000 in checks for safekeeping.
Stephen lost his job as an Oak Brook, Ill., police officer for failing to disclose details of interactions he had with his dad after the disappearance. And he's run through his pension raising his father's children. So when Lifetime called with a $10,000 offer to be on the show Monster in My Family, Stephen took the deal. He says he told his father about the show, which details the life Stephen, now 37, has had with Drew and Stacy's two children, who are in middle school; Stephen also looked after Drew's sons with Savio, who are now young adults. Stephen says there was no "a-ha moment," when he changed his mind about his father's role in Stacy's disappearance, but he does recall her fear after Savio's death. "You kind of look back and think, maybe she did know something, or maybe something did happen," Stephen says. Drew, now 63, is imprisoned at Menard Correctional Center; he was recently sentenced to another 40 years for conspiring from prison to kill the prosecutor who put him there. His family has yet to visit. (Read more Drew Peterson stories.)