Amanda by Night (1981)

Amanda Heather is a high-class call girl trying to go straight. A last "favor" for a former pimp/lover results in the death of one of Amanda's young prostitute friends and she is inexorably drawn into a spiral of brutality, corruption, violent sensuality, and ever-building tension as the murderer stalks her. Amanda's emotions are brought to the boiling point by the persistent, tormenting questions of detective Ambrose Harte as he struggles to solve the murders and free Amanda from the treacherous web of lust that is her "working" life.