For twenty years, Sheriff David Reichert of King County, Washington, was a man with a single, all-consuming obsession: to capture the most notorious serial killer in American history — the monster who would become known nationwide by the river he used as a dumping ground. From the earliest morning hours to the middle of the night, Reichert combed local streets and alleys, wilderness and parkland, searching for any clue that could lead him to the Green River killer. He was driven by compassion for the victims’ families and justice for the victims. He staked his career and his life on putting an end to the most horrifying episode in his beloved county’s history.