Mary Parks, a former classmate at Joliet Junior College, recalled a conversation in the fall of 2003 when Savio told her about an altercation she had with her husband the day before, the Chicago Sun-Times reported.
Parks told the Joliet courtroom Savio showed her three red marks on her neck, saying Peterson, a former Bolingbrook police officer, had put them there.
"He grabbed her by the neck and he pinned her down," Parks said Thursday. "She said that her husband at that point said to her, 'Why don't you just die?' "
Defense lawyers tried to discredit Parks' testimony, questioning why she at one point told investigators the conversation happened in the fall of 2002.
"Yes, I misspoke," she said.
Peterson lawyer Steve Greenberg said transcripts from the school indicate Parks didn't have any classes with Savio during the fall of 2003, the Sun-Times reported.
Peterson is charged in the March 2004 drowning death of Savio, his third wife, and is the prime suspect in the disappearance of his fourth wife, Stacy Peterson.