Authorities scoured a northern Illinois county after night fell in the search for three people wanted in the fatal shooting of a police officer.

Lake County Sheriff's Office spokesman Sgt. Christopher Covelli says helicopters will fly overnight and about 100 officers will search in and around Fox Lake for the suspects in Tuesday morning's shooting of Lt. Charles Joseph Gliniewicz.

Authorities say the 52-year-old Gliniewicz radioed in to tell dispatchers he was chasing three men on foot in the village of Fox Lake, 55 miles north of Chicago. Covell says communication with him was lost soon after.

Authorities say the 30-year veteran was married with four children.

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