"A Shot in the Dark" (1964) was based upon a stage play that originally did not include the Clouseau character. In this film, Sellers began to develop the exaggerated French accent that later became a hallmark of the character. The film also introduces two of the series regular characters: his superior, Commissioner Dreyfus (Herbert Lom), who is driven mad by Clouseau's blundering of the investigation; and his long-suffering Chinese manservant, Cato (Burt Kwouk), who is expected to improve Clouseau's martial arts skills by attacking him at random.