Infernal Affairs (2002)

A story between a mole in the police department and an undercover cop. Their objectives are the same: to find out who is the mole, and who is the cop.

Directors:
Wai-keung Lau, Alan Mak
Writers:
Alan Mak, Felix Chong
Stars:
Andy Lau, Tony Leung Chiu Wai and Anthony Wong Chau-Sang.

Storyline

Chan Wing Yan, a young police officer, has been sent undercover as a mole in the local mafia. Lau Kin Ming, a young mafia member, infiltrates the police force. Years later, their older counterparts, Chen Wing Yan and Inspector Lau Kin Ming, respectively, race against time to expose the mole within their midst. Written by Aya .

this movie released on 2002. and its nice movie. its a hit movie, on that time.