Angel Heart

The time is the 1950s: seedy Brooklyn private eye Harry Angel (Mickey Rourke) is hired by shady Louis Cyphre (Robert De Niro) to locate a pop singer who reneged on a debt. Harry ventures into Harlem, the first step of a Heart of Darkness-inspired odyssey. Each time Harry makes contact with someone who might know the singer’s whereabouts, he or she is killed in a horrible, ritualistic fashion; a Satanic cult seems to be at the bottom of all the carnage. Harry solves the mystery, all right. He just didn’t know that he had the answer all along — even before Louis entered his office.

source