"I heard screaming upstairs and her friend Mary went upstairs and she was dead in the bathtub," Peterson said. "I checked for life signs and I knew at that particular time I didn't belong there, so I called for additional police units to show up and take charge of the scene."
Peterson revisited the scene of Savio's death during our January 2009 interview. He seemed remarkably detached and unemotional as he recalled finding his ex-wife, dead, with a gash in her head.
"It's my kids, I got them out of their as quickly as possible after it happened. They went back for their things and it was kind of emotional, but it was kind of like what can you do? Life goes on," Peterson said.
According to the original autopsy, Savio drowned accidentally. Within a year, Peterson married his fourth wife, Stacy, and they had two children. In 2007, Stacy Peterson disappeared.
Police never located Stacy, but they did find e-mails she allegedly sent to friends, revealing intimate details of her relationship with Peterson, calling it "controlling, manipulative and somewhat abusive."
Peterson questioned the authenticity of the e-mails in the January 2009 "Nightline" interview.
Stacy Peterson's minister, Neil Schori, also spoke with us, claiming the reason Stacy disappeared was because she knew the truth about how Peterson's third wife had died.
Again, Peterson questioned the minister's story and legitimacy.
"I heard that, but again, wouldn't you seek out authorities if you heard that coming out of somebody's mouth? And I really question whether she really said it or it's something he fabricated," Peterson said. "But from my understanding, the minister's story has changed since he initially said this."
Schori, who testified in last month in the pretrial hearing, previously claimed that Stacy told him Peterson murdered Savio. He later said that Peterson told Stacy to lie about his whereabouts the night of Savio's murder.
Savio allegedly wrote to former Assistant State's Attorney Elizabeth Fragale, expressing fears that her estranged husband might kill her. She also appears to have written a letter to a friend, Pam Bosco, saying, "I love you, if anything happens to me, he killed me. It wasn't an accident."
Savio's family and neighbors have come forward in Peterson's pre-trial hearing, saying each woman expressed a deep and profound anxiety that her husband was going to kill her.
Peterson's defense attorneys said that despite the testimony, the defense has failed to prove Peterson was involved in Savio's death.
"Why is it that so many people from varied backgrounds… all seem to be saying that his wives told them that he was likely to kill them?" said Peterson's attorney, Joel Brodksy. "I think it's almost like, call it a mob effect, a lynch mob effect. Everyone wants to jump on the bandwagon because they want a result."
"Things are never that consistent," Brodsky said, "So when you have this, what I call eerie consistency, I think it really gives rise to lessening the credibility rather than strengthening it."
The defense maintains that Drew Peterson cannot be convicted of murder on the basis of hearsay.