Violent Cop / Sono otoko, kyôbô ni tsuki (1989)

Detective Azuma is a Dirty-Harry style rogue cop who often uses violence and unethical methods to get results. While investigating a series of drug-related homicides, Azuma discovers that his friend and colleague, Iwaki, is supplying drugs from within the police force. After Iwaki is murdered and Azuma's sister is kidnapped, he breaks all the rules to dish out his particular form of justice.