Philip D'Antoni, who had produced Friedkin's 1971 film "The French Connection", approached Friedkin with the idea of directing a film based on "New York Times" reporter Gerald Walker's 1970 novel "Cruising" about a serial killer targeting New York City's gay community. Friedkin was not particularly interested in the project. D'Antoni tried to attach Steven Spielberg, but they were not able to interest a studio. A few years later, Jerry Weintraub brought the idea back to Friedkin, who was still not interested. Friedkin changed his mind following a series of unsolved killings in gay leather bars in the early 1970s and the articles written about the murders by "Village Voice" journalist Arthur Bell. Friedkin also knew a police officer named Randy Jurgensen who had gone into the same sort of deep cover that Pacino's Steve Burns did to investigate an earlier series of gay murders, and Paul Bateson, a doctor's assistant who had appeared in Friedkin's 1973 film "The Exorcist", who, while being prosecuted for another murder, was implicated (but never charged) in six of the leather bar murders. All of these factors gave Friedkin the angle he wanted to pursue in making the film. Jurgensen and Bateson served as film consultants, as did Sonny Grosso, who earlier had consulted with Friedkin on "The French Connection". Jurgensen and Grosso appear in bit parts in the film.