William Friedkin's dark, highly controversial lurid thriller about an undercover cop named Steve Burns, compellingly played by Al Pacino in low-key understated performance, who goes underground into the gay S&M leather subculture of New York City during the pre-AIDS early 80s to try and catch a sadistic serial-killer of homosexual men. Burns who is straight goes deep cover as a gay man and a decoy for the murderer, he is completely isolated from the police department and his only contact is his superior Captain Edelson, superbly played by Paul Sorvino. He cannot even tell is girlfriend, nicely played by Nancy Alien, about his assignment. But as the vicious murders continue Burns is starting to be affected by his exposure to the hardcore gay lifestyle and it begins to change him. Okay direction by Friedkin, who also wrote the confusing and sometimes awful screenplay which is based on the novel by Gerald Walker. Striking cinematography by James A. Contner, and a marvelous original score by the late Jack Nitzsche. The only real reason to see this film is for Al Pacino's captivating performance, otherwise this motion picture is truly a mess, but fascinating never the less. Note: This film when released in 1980 caused many gays to protest the film for it's degrading and distasteful view of the gay community. Homophobic, ambiguous, brutal and not for all tastes. Recommended.