JOLIET, Ill. — Just two days after his third wife's body was found in a bathtub, Drew Peterson sat on a card-table chair next to his tearful fourth wife and corrected at least one of her answers as state police interviewed her about the death, the lead investigator told jurors on Wednesday.

The dramatic testimony came as prosecutors in Peterson's murder trial continued to try to show that the initial investigation into the 2004 drowning of 40-year-old Kathleen Savio was badly botched and that investigators overlooked potentially key evidence as they rallied to protect a fellow officer from scrutiny.

Peterson — charged in Savio's death only after his fourth wife, 23-year-old Stacy Peterson, went missing in 2007 — had his hand on Stacy's knee and his arm around her shoulder during the interview in the basement of the couple's home, retired Illinois State Police sergeant Patrick Collins said.