Lake County Major Crimes Task Force Cmdr. George Filenko said an officer was shot Tuesday morning near Rollins Road and Route 59.
Sources told CBS Chicago that the officer had died but police officials have yet to comment publicly on the officer's condition.
According to sources, it started with a traffic stop on Rollins Road, when pepper spray was deployed, and the officer was shot.
People in the area were being told to stay inside their homes and businesses. Grant Community High School in Fox Lake and St. Bede School in neighboring Ingleside were placed on lockdown at the request of Fox Lake Police as police search for the suspects.
Gavin School District 57 said Gavin South Middle School and Gavin Central Elementary School -- both in Ingleside -- were on soft lockdown. McHenry School District 15 said all of its schools -- six elementary schools and two high schools -- also were on soft lockdown due to the manhunt.
Police were searching for a white male and a black male, and possibly a female as well. Unconfirmed dispatch reports indicated the suspects might have taken the officer's gun and pepper spray.
The manhunt appeared to be centered on a marshy area off Rainier Way and Rollins Road. Police officers from at least a half dozen different agencies - many heavily armed and wearing body armor - have scattered throughout the area. Several law enforcement vehicles, including armored trucks, were lining U.S. Route 12 in Fox Lake.
K-9 units and helicopters also have been brought in, and according to unconfirmed dispatch reports, picked up a scent in that swampy area.
The manhunt also has affected trains on the Milwaukee District/North Line, which ends in Fox Lake. At least one train has been stopped due to the police activity, and the Ingleside station has been closed. Passengers on one train from Fox Lake to downtown Chicago will be bused to the Long Lake station.
Service disruptions on the Milwaukee District/North Line were likely until the manhunt ends.
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