JOLIET, IL - Prosecutors are expected to rest their case at former police officer Drew Peterson's murder trial.
 
Heading into Monday, they've called more than 30 witnesses over a month in their bid to prove Peterson killed his third wife, Kathleen Savio, in 2004.
 
After the state rests, the defense is expected to ask the judge to enter a not guilty verdict before jurors even begin deliberations.
 
Such "directed verdicts" are rarely granted. But the lack of any physical evidence and the state's reliance on hearsay evidence makes it a possibility in Peterson's case.
 
If the motion isn't granted, Peterson's lawyers would have their opportunity to start calling their own witnesses.
 
Peterson has pleaded not guilty to murdering Savio. He was only charged after his fourth wife, Stacy Peterson, went missing in 2007.