The Fox Lake, Ill., police officer shot and killed while chasing three suspects Tuesday morning was a 30-year veteran of the force who went by the nickname "G.I. Joe" and was married with four children, according to police and family, reports the Chicago Tribune .

"He's got four sons who are going to have to go on alone," said Terry Resetar, mother-in-law of the slain officer, Charles Joseph Gliniewicz, 52.

Gliniewicz radioed shortly before 8 a.m. while on routine patrol that he was going to check on some suspicious activity, Lake County sheriff’s spokesman Chris Covelli said during a news conference.

He then radioed he was in a "foot pursuit" but communication was lost after that, Covelli said. Other officers responded and found him shot near Route 12 and Sayton Road, he said.

Gliniewicz was discovered in a marshy area, stripped of his gun and other gear, according to Lake County Undersheriff Raymond Rose. He died at the scene, the undersheriff said.

Police established a perimeter and sent helicopters into the air as they sought three suspects, described only as a black male and two white males, Rose said. Several canine units were also dispatched, as well as SWAT teams in camouflage.

With the help of U.S. marshals, teams of police from throughout the county searched surrounding woods and businesses in the area. By 4 p.m., no arrests had been made as more than 100 police officers continued the search.

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