CHICAGO (CBS) -- The son of convicted killer and former Bolingbrook police sergeant Drew Peterson has revealed he believes his father "probably" killed his third wife, Kathleen Savio, and his fourth wife, Stacy Peterson.
Stephen Peterson has been raising his father's four children in his father's home while Drew Peterson has been serving a 38-year prison sentence for the 2004 murder of his third wife, Kathleen Savio. Illinois State Police also have named Drew Peterson a suspect in the disappearance of his fourth wife, Stacy, although he has never been charged in that case. Stacy Peterson's disappearance prompted authorities to reopen the investigation of Savio's death, leading to Drew Peterson's conviction for murder.
In an interview on Lifetime cable network show "Monster In My Family," Stephen Peterson said he initially believed his father's claims his third wife drowned accidentally and that Stacy left him for another man, but that he eventually grew to believe his dad killed Savio.
"I'd probably say so," he said. "I think this is the first time I ever even said that out loud that I think he probably did it."
Stephen Peterson also said he believes his father probably killed Stacy, who remains missing.
Stacy's sister, Cassandra Cales, says she first heard about the show from friends.
"His conscience is finally catching up to him," she tells CBS 2's Roseanne Tellez.
This brings little relief. Cales say the Stephen Peterson son doesn't allow her to see Stacy's children, whom he's now raising in his father's old house. She thinks he's looking for sympathy.
While Stephen Peterson says he still loves his father, and remembers him as a good dad, he said he knows his father thinks only of himself.
"I don't think he fully realizes what he has done to Stacy's family, Kathy's family, our friends, the kids, everybody," he said. "I'm not my father, and if I screw up, I own what I do. It's something he will never do. He did not take into consideration anybody except himself."
Stephen Peterson had not spoken to Savio's sister, Sue Doman, since Savio's funeral, until the two met for the show. Doman told him she hates his father, and asked Stephen to deliver a message to Drew.
"I want to tell you to tell him something for me. I want to hurt him," she said.
Stephen Peterson said he understands how Doman feels about his father, "and that's okay," but he said he is not his father.
"I understand I sound like him, and I have his laugh, and at the right angle I even look like him a little bit, but that's not me," he said.
On the show, Stephen Peterson recalled often hearing his father and Savio arguing in the middle of the night while he and his brother were in bed. He said the fights were sometimes so bad, when he woke up the next morning, "the house would be destroyed."
He also said his father repeatedly cheated on his wives with younger women, and noted that Stacy Peterson acted scared after Savio's death, though he dismissed her fears at the time.
"You kind of look back and think, maybe she did know something, or maybe something did happen, but at the time we never thought twice about it," he said.
Stephen Peterson acknowledged he appeared on "Monster in my Family" for the money, because his father's pension payments have ended, and he was using the pension to help support his father's children after Stephen was fired as a police officer in 2011.
He lost his job as a police officer in Oak Brook, after he was accused of obstructing the investigation into Stacy's disappearance by hiding his father's guns.
The Oak Brook Board of Fire and Police Commissioners ruled Stephen failed to disclose Drew had given him three guns and checks totaling nearly $240,000 just three days after Stacy vanished in October 2007, and later claimed they were irrelevant to the investigation.
Stephen said he didn't suspect anything was wrong at the time his father gave him the guns and money.
"He's your dad and you don't think twice," he said. "Why would my dad put me in a bad position?"
Drew Peterson was sentenced to 38 years in prison for Savio's murder. After he went to prison, he also was convicted of trying to hire a fellow inmate to kill Will County State's Attorney James Glasgow, who prosecuted him. He was sentenced to an additional 40 years in prison for the murder-for-hire plot.
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