Stacy Peterson, 23, disappeared in Oct. 2007. She was Drew's fourth wife. Investigators previously tracked cell phone activity from Stacy's number to the Shorewood area about the time she was last seen.
The search on Monday in Hammel Woods is not believed to be linked to new information or specific tips and an Illinois State Police source said that they did not find a body.
The ISP was assisted on Monday by the FBI. Neither agency would speak officially about the operation-except to say it was part of an on-going criminal investigation.
Peterson is the prime- and only- suspect in the disappearance of Stacy. He hasn't been charged in connection with her case, but was convicted two months ago of killing his third wife, Kathleen Savio.