Little Cop

Little Cop is a 1989 Hong Kong comedy film directed by Eric Tsang, starring Tsang and Natalis Chan. The film also features cameo appearances from many Hong Kong celebrities such as Andy Lau, Alan Tam, Jacky Cheung and Maggie Cheung.

He is later transferred, first to the AntiPorno Bureau where he falls in love with a call girl, then to the Regional Crime Unit where he works under Inspector Chu Natalis Chan. During a drug raid operation, Lee kills drug lord Ng Cheung. Ngs father hires a killer, Thousand Faces Man Michael Miu, to take revenge on Lee. After several confrontations, Lee finally brings Thousand Faces Man to justice.The corrupt director of a mental hospital places Lee in the mental hospital for a year, during which time he develops mental disorders. After being discharged from the hospital, he becomes a restaurant waiter. ........

Source: Wikipedia