A Certain Killer (Japanese: ある殺し屋, Hepburn: Aru Koroshiya) is a 1967 Japanese crime suspense film directed by Kazuo Mori. Screenplay by Yasuzo Masumura and Yoshihiro Ishimatsu. It stars Raizō Ichikawa. The film was adapted from the novel Zenya written by Keishi Nagi. Sequel of the film Aru Koroshiya no Kage was released in the same year.