Police in northern Illinois have expanded the search area for three suspects in Tuesday's murder of a Fox Lake police officer.

Lt. Joe Gliniewicz, a 52-year-old father of four and 30-year veteran of the force, was gunned down Tuesday morning after telling dispatchers he was pursuing three male suspects on foot.

Gliniewicz's service weapon was taken after he was shot. 

Officers who rushed to the scene found Gliniewicz dead in a marshy area near U.S. Highway 12.

On "Happening Now" this morning, Mike Tobin reported from Fox Lake that authorities do not believe the suspects are within the two-mile search perimeter they established after the shooting.

Tobin said police believe they exhausted their efforts to find the men within that area. He said the manhunt has moved to "saturation patrols" over a wider area.

All that is known about the suspects at this point is that two are white and one is black. 

Tobin said life appears to be returning to normal in Fox Lake, though seven schools in the town remain closed. 

Watch his report above.