The shooting death of a police lieutenant made national news and brought a stretch of northern Illinois to a tense standstill with roadblocks, thudding helicopters and officers tramping with dogs through woods and over farmland, searching for the killers. The lieutenant, Charles J. Gliniewicz, was hailed as a hero, and some conservatives seized on this and other shootings as evidence that critics of the police were fueling a wave of violence against law enforcement.

But on Wednesday, more than two months after Lieutenant Gliniewicz was found dead in Fox Lake, a small town northwest of Chicago, law enforcement officials said the truth was something very different: He took his own life.

Still more surprising was the explanation they offered. They said that Lieutenant Gliniewicz, 52, a local fixture admired for his work with young people, had been stealing money from the town for years and feared he was about to be caught.