BOLINGBROOK, Ill. (CBS) -- It was just before Halloween four years ago that Bolingbrook mother Stacy Peterson vanished. Since then, her husband Drew Peterson has been charged in the death of his previous wife, Kathleen Savio.
But exactly what happened to Stacy Peterson remains a mystery. Drew Peterson has been named a person of interest in her disappearance, but has not been charged with a crime in that case.
On Tuesday, her sister Cassandra Cales spoke exclusively to CBS 2's Mike Puccinelli and she has a very clear message for Drew Peterson.
"I hope you regret what you've done, taking someone so sweet and so fragile away from your family and you -- and me and my family," Cales said. "She meant no harm to you and she wasn't going to take all your money and everything. You just couldn't live with her being with another man. She loved you very much and she just couldn't put up with your jealousy and that's what we talked about the night before you murdered her."
Cales has long maintained she believes Drew Peterson killed her sister.
"She was the brightness in my day every day. If I was having a bad day. I would call her. You know, she would cheer me up. If she was having a bad day she would call me, I would cheer her up."
Cales said she used to take those calls with her sister for granted, but not anymore.
Asked what she misses most about Stacy after four years, Cales said, "Everything, I mean there wasn't a thing that I didn't like to do with her."
And now, since she can't do anything with Stacy, she just wishes she could spend time with Stacy's two young children, but she says Drew Peterson won't let that happen.
"He hurt me by taking away my sister and now he's trying to hurt me even more by keeping her kids away from me," Cales said.
She said the next few days are going to be difficult, but she also believes they're going to be difficult for Drew Peterson as he sits in jail with only his conscience to keep him company.
Drew Peterson has never been charged in the disappearance of Stacy Peterson, but police say he is the only suspect in her disappearance and presumed death. He is expected to go on trial for the murder of Kathleen Savio next year.
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