"The Amityville haunting is based on the true crimes of Ronald DeFeo Jr. On November 13, 1974, DeFeo shot and killed six members of his family at 112 Ocean Avenue, Amityville, on the south shore of Long Island.
He was convicted of second-degree murder in November 1975. In December 1975, George and Kathy Lutz and their three children moved into the house. After 28 days, the Lutzes left the house, claiming to have been terrorized by paranormal phenomena while living there.
The house became subject of numerous investigations by paranormal researchers, journalists, and skeptics including Ed and Lorraine Warren.
These events served as the historical basis for Jay Anson's 1977 novel The Amityville Horror, which was followed by a number of sequels and was adapted into a film of the same name in 1979."