JOLIET, IL - Drew Peterson's attorneys are hoping to dent the credibility of his vanished fourth wife heading into their second day presenting evidence as they seek to show he didn't murder his third wife.
 
The judge is expected to decide Tuesday if the defense can ask a witness if Peterson's fourth wife, Stacy Peterson, sought to squeeze her husband for money by threatening to tell police he killed his third wife.
 
The former suburban Chicago police officer has pleaded not guilty to murdering Kathleen Savio in 2004. He was only charged after Stacy Peterson went missing in 2007.
 
Prosecutors had entered hearsay evidence that Stacy Peterson blamed her husband in Savio's death.
 
Stacy Peterson is presumed dead. Drew Peterson is a suspect in her disappearance but isn't charged in her case.