In 1974 DeFeo murdered his entire family, including his mother, father, and four siblings, with a .35 caliber Marlin lever-action rifle in Amityville, Long Island. The murders were the basis for the 1979 film "The Amityville Horror, A True Story."
DeFeo was convicted on December 4, 1975 and was sentenced to six sentences of 25-to-life by Judge Thomas Stark. Shortly after the DeFeo murders, the Lutz family moved into the Long Island home but left a month later due to the house's immense paranormal activity.
DeFeo died in New York state custody on Friday, March 12, 2021, at 69.