Prime Suspect 3 (1993)

Detective Chief Inspector Jane Tennison moves to a new district and is put in charge of a vice investigation instead of homicide. But soon a homicide case impinges on her new job when a very young male prostitute is murdered in the apartment of Vera Reynolds, a female impersonator. Soon Jane is on the trail of the boy's brutal young pimp (played by David Thewlis). But her investigation is complicated by the Old Boy's Network, which is spying on her and is more concerned with preventing scandal than bringing the villain to justice.
from imdb, written by Reid Gagle