Xie zheng (1973)

During a night, a mechanic is the involuntary witness of a brutal homicide. He goes to the police and from that moment on he and his family becomes the targets of a Triad gang revenge. A cop named Apple is assigned to them as bodyguard, as the gangsters tries everything to kill the witness, including send to him a box full of snakes. Pushed to the extreme, the man will go into a ruthless revenge.