On November 13, 1974, 18-year-old Dawn Theresa DeFeo was found among six members of the DeFeo family shot dead in their Ocean Avenue home in Amityville, New York. Dawn and her parents, Louise and Ronald DeFeo Sr., and her younger siblings Allison, 13, Marc, 12, and John, 9, were discovered lying face down in their beds.

Their older brother, 23-year-old Ronald Butch DeFeo Jr., initially went to a local bar saying his parents had been shot. Police later determined his account of a mob hit was false; the following day he confessed. Investigators recovered a .35-caliber Marlin rifle that had been discarded in a nearby canal. DeFeo Jr. was charged with six counts of second-degree murder, tried beginning October 14, 1975, and convicted on November 21, 1975. He received six concurrent terms of 25 years to life.

Over time DeFeo Jr. gave different versions of what happened, once accusing Dawn of involvement—a claim that was never substantiated and that he later contradicted. The motive for the familicide remains unclear. Did anyone in the Amityville area at the time notice anything out of the ordinary that night?