Red to Kill (1994)

Ka Lok Cheung (Man Yee Lo), a disenchanted social worker, takes on the case of a mentally disabled woman, Ming-Ming (Lily Chung), whose father has been killed in a car accident. She finds Ming-Ming at a home for the mentally ill, run by the kindly Chan (Ben Ng). Cheung spends time with Ming-Ming, draws her out of her shell, and teaches her to dance. Meanwhile, the neighborhood is being terrorized by a murderous, slobbering rapist. The locals blame the group home for all the mayhem, until the patients team up to stop a drunken pervert from molesting a schoolgirl. The neighbors are won over, but the real menace is still at loose. Ming-Ming soon learns the horrible truth. Chan, haunted by a childhood trauma, flies into a psychopathic rage whenever he sees a woman wearing red. He brutally rapes Ming-Ming, but decides not to murder her. Ming-Ming is extremely distraught and confused, and makes a poor witness against Chan when the case comes to trial. When Chan is freed, Cheung decides to get revenge. Red to Kill was directed by Billy Tang. ~ Josh Ralske, Rovi