Police ended the search for three people wanted in connection with the shooting death of a Fox Lake, Illinois, police officer, but the investigation continues, Lake County Major Crime Task Force Commander George Filenko said Wednesday.With almost no time to grieve, law enforcement officers continue scouring the deeply wooded areas of northern Illinois to look for Lt. Joe Gliniewicz's killer.

The 32-year police veteran was on patrol Tuesday morning when he made a radio call saying he was running after three suspicious people, the Lake County Sheriff's Office said.

That was the last time anyone heard from him. Fellow officers from Fox Lake Police Department arrived to find their colleague shot to death.The FBI, U.S. Marshals and the Bureau of Alcohol, Tobacco, Firearms and Explosives have joined in the hunt. But the search for the three suspects has proven arduous.Well over 100 law enforcement officers have raked through the heavy woods near Fox Lake on foot, all-terrain vehicles and horseback.Some had K-9 partners. Helicopters aided the search.