Coming face to face with America's worst killers, FBI agent Robert K. Roessler learned to recognize the unknown monsters that walk among us and put them in jail. He used evidence at the crime scene and compiled psychological portraits of the killers - from the victims they choose to the method of murder and often quite grotesque souvenirs they take from the victims. Roessler conducted dozens of interviews behind prison walls and studied strange firsthand stories from countless convicted murderers, including Ted Bundy, John Wayne Gacy, Edmund Kemper. Join Robert K. Roessler, he will lead you on a hunt for the most dangerous psychopaths in the world.