"The Amityville Horror" is a horror novel from 1977 by Jay Anson. Based on this book there has been a series of films around 20 years after the release of the book. The novel is claimed to be based on a true story but many people doubt of its truthfulness.
The book, and therefore the movies, are based on the paranormal experiences of the Lutz family in a house in Amityville. This family moves into the house around a year after the "DeFeo murders" - Ronald DeFeo Jr. killed six of his family members in this house on November 13, 1974.
The quotes listed in this post are all from "The Amityville Horror" movie.