After grossing over 1.5 billion Italian lire in Italy with his first horror film ("Zombi 2"), director Lucio Fulci began working on a new horror script with screenwriter Dardano Sacchetti. Elements of the story are influenced by the work of H.P. Lovecraft, such as naming the town the film is set in Dunwich, after Lovecraft's "The Dunwich Horror". Sacchetti noted that Fulci had just reread Lovecraft before working on the film's script, stating he wanted to re-create a Lovecraftian atmosphere. In Sacchetti's original writings, the story is not set in Dunwich, but Salem. This script also includes characters not used in the film, such as Gerry, a psychoanalyst, and Mike, a homeless man who is devoured by cats and reappears later in the film as a zombie.