A police K-9 team takes a break in the search for suspects in the shooting of a police officer in Fox Lake, Ill., Sept. 1, 2015.
A police K-9 team takes a break in the search for suspects in the shooting of a police officer in Fox Lake, Ill., Sept. 1, 2015.

FOX LAKE, ILLINOIS - Armed police with helicopters and dogs conducting a massive manhunt in northern Illinois on Tuesday after an officer was fatally shot while pursuing a group of men.

An emotional Fox Lake Mayor Donny Schmit described the slain officer, Lieutenant Charles Joseph Gliniewitz, as a personal friend, a three-decade member of the department and a father of four sons.

"We lost a family member,'' Schmit said of the 52-year-old officer known around town as "GI Joe.'' "His commitment to the people of this community has been unmatched and will be dearly missed.''  

Authorities said Gliniewitz radioed in to tell dispatchers he was chasing three men on foot in Fox Lake, north of Chicago. Communication with him was lost soon afterward, said Lake County Sheriff's Office spokesman Sergeant Christopher Covelli.

"His backup arrived shortly thereafter and found him injured with a gunshot wound,'' Covelli said. "The officer has succumbed to his injuries.''

Undersheriff Raymond Rose told the Chicago Tribune that the officer had also been stripped of his gun and other equipment.

The Fox Lake area is popular with those who pursue outdoor activities because of its forest preserves and a chain of lakes. Some longtime city dwellers move to the region for what is normally a quieter lifestyle.

Police and other law enforcement officials, some in military-style camouflage, were seen taking up positions on rooftops and along railroad tracks, scanning the terrain with rifle scopes and binoculars. Others leaned out of helicopters with weapons at the ready.

Nearby Grant Community High School was placed on lockdown, with children and staff instructed to say hidden and away from windows, and Schmit said that other schools were also put on lockdown, as staffers went from room to room to make sure the children were safe.

Authorities urged residents throughout the area to stay home while they searched for three men, two of them white and the other black.

The service of a local commuter train was halted, and residents who wanted to take their dogs out to relieve themselves were told to stay in their homes, with the job of walking the dogs handled by police officers.

Gliniewicz's death was the third law enforcement fatality in Illinois this year, according to the Law Enforcement Officers Memorial Fund. It said firearms-related deaths in the U.S. were down 13 percent this year compared with the same period last year, January 1 to September 1; there were 30 last year and 26 this year.