FOX LAKE, Ill. (AP) — Authorities in northern Illinois have expanded their search for three suspects wanted in the shooting death of a police officer.

Lake County Sheriff’s Office spokesman Sgt. Christopher Covelli says local and state police have been conducting

Fox Lake Lieutenant Charles (Joe) Gliniewicz was gunned down just before 8 a.m. while responding to a report of a suspicious group, police said.

Fox Lake Lieutenant Charles (Joe) Gliniewicz was gunned down just before 8 a.m. while responding to a report of a suspicious group, police said. PHOTO- NYDailyNews

“saturation patrols” in the Fox Lake area since late Tuesday night when they exhausted a search of a tighter, two-square-mile perimeter.

Covelli says that besides catching the offenders, the heavy police presence is meant to reassure the community. Seven schools were closed Wednesday out of concern for children’s safety.

Authorities say 52-year-old Lt. Charles Joseph Gliniewicz was shot dead Tuesday morning while pursuing three suspicious men on foot in the community 60 miles north of Chicago.

The 30-year veteran was married with four children.