In the early hours of August 15, 1967, Canada was rocked by one of the most horrific tragedies in its history—the Peterson family massacre in Shell Lake. Nine family members were brutally murdered by a man named Victor Hoffman, who had just been released from a mental hospital. Hoffman claimed to hear demonic voices commanding him to kill. He believed he was carrying out a divine mission to exterminate the devil himself. From mystical visions to uncontrollable urges to kill, this story reveals the darkest side of the human soul and how the mental health system of the 1960s failed to recognize the real danger.