Sipple's mental and physical health sharply declined over the years. He drank heavily, was diagnosed with schizophrenia, fitted with a pacemaker, and gained weight. The incident brought him so much attention that, later in life, while drinking, he would express regret about grabbing Moore's gun. On February 2, 1989, an acquaintance, Wayne Friday, found Sipple dead in his San Francisco apartment, with a bottle of Jack Daniel's next to him and the television still on. The San Francisco coroner estimated Sipple had been dead for approximately 10 days. He was 47 years old. President Ford and his wife sent a letter of sympathy to Sipple's family and friends. He was buried in Golden Gate National Cemetery south of San Francisco.