 The cult featured in the film, the Black Circle, was based on an  actual group. In 1984, in Northport, Long Island, a few High School  dropouts formed a cult named the Knights of the Black Circle. Two of  its members, who were both heavily involved in drugs, brutally  murdered one of their friends when he refused to profess allegiance  to Satan. Their story became the basis of the book, "Say You Love  Satan". Incidentally, the exteriors of the Besler house were shot in  Northport, only one block away from the crime scene itself.