Murderer is a co-production between
Focus Features, EDKO Film, and
Sil-Metropole Organisation. The film marks the directorial debut of Roy Chow, and features action choreography by
Chin Kar-lok. During production,
Aaron Kwok went without sleep for his role. On set, he became known as "
Iron Man Kwok." Kwok in order to convey the most disturbed emotions, did not say much for nearly a day. He would often sit in a corner without saying a word and looked very vicious. crew members warned each other not to go near Kwok. When production for the film ended, Kwok did not sleep for three days, despite feeling completely exhausted.
Cheung Siu-fai, who co-stars in the film, had to overcome his fear of heights for film, as he had to jump down a five-story platform to a ground full of sharp rocks. After Chin Ka-Lok demonstrated that stunt to him, Cheung agreed to perform it himself. In order to break his fall, Cheung used his arms to block the edges of sharp rocks from hitting his head. Despite being shaken after performing the stunt, Cheung described his fall as intense and exciting: "Although I am afraid of heights I feel this scene is very refreshing and challenging." ==Release==