Kathleen Savio was so fearful of her husband, Drew Peterson, that she slept with a knife beneath her mattress, a friend of the deceased woman testified in court.
Peterson, a 58-year-old former Bolingbrook police sergeant, is on trial on charges he killed Savio.
Wednesday's so-called "hearsay" testimony from Kristin Anderson was allowed following an explosive argument between Judge Edward Burmilla and Will County State's Attorney James Glasgow.
Anderson, a key prosecution witness, broke down and briefly left the courtroom sobbing after she started to talk about how Savio once said Peterson had bragged that, "'I could kill you and make it look like an accident.'"
When Savio's friend returned, she told jurors in detail how Savio described how Peterson broke into her house while wearing SWAT gear and made the ominous threat at knife point.
Anderson said she lived at Savio's house temporarily while her own home was under construction.
During cross-examination, defense attorney Joel Brodsky raised his voice, pressing Anderson repeatedly about why -- if the threat was so unsettling -- she didn't move out.
"You didn't move out, did you? ... You didn't call the police either ... You did nothing ... because you didn't believe her, that's why," Brodsky shouted over the objection of prosecutors.
"Sir, no one listened to Kathy," Anderson added later. The judge told jurors to disregard that.
Earlier, a lead investigator, retired Illinois State Police sergeant Patrick Collins, testified that Peterson sat with his fourth wife, Stacy Peterson, as she was being interviewed about Savio's death.
Stacy Peterson was clearly upset during the interview, which Collins said came just two days after Savio's body was found.
Collins recalled that Drew Peterson requested to be present during the questioning and at one point put his arm around his wife and even coached her through an answer about what she cooked for breakfast.
"There was one particular question where he did have to refresh her memory," Collins testified.
The dramatic testimony came as prosecutors continued to try to show that the initial investigation into Savio's death was badly botched and that investigators overlooked potentially key evidence as they rallied to protect Peterson, a fellow officer, from scrutiny.
Collins conceded it was unusual to let one potential witness sit in on the interview of another, saying he had never done it before and never did it again.
It was a fact that flabbergasted Savio's family and friends.
"To have him sitting right beside her was insane. It was the worst possible thing you could do for an interview like that," Savio's friend, Pam Bosco, said outside the courthouse after proceedings ended for the day.
Stacy Peterson vanished in 2007. Outside observers may be inclined to link Savio's death to Stacy Peterson's disappearance, but jurors aren't supposed to make any such links.
Burmila has prohibited prosecutors from telling jurors Stacy Peterson is presumed dead or that Drew Peterson is a suspect in her disappearance. He is not charged and insists his fourth wife left him for another man.
- Day 1: Peterson Trial Begins with Different Explanations of Savio's Death
- Day 2: Judge Could Declare Mistrial in Peterson Case
- Day 3: Judge Denies Motion for Mistrial in Peterson Case
- Day 4: Savio's Sister Testifies
- Day 5: Colleague: Drew Peterson Said Life Would be Better if Savio Were Dead