Homicidal is a 1961 thriller film produced and directed by the self-proclaimed "King of Showmanship", William Castle. Written by Robb White, the film stars Glenn Corbett, Patricia Breslin, Eugenie Leontovich, Alan Bunce, and the enigmatic Joan Marshall (billed as Jean Arless). It was released with a "fright break" that allowed patrons to receive a refund if they were too scared to stay for the climax of the film.

The story centers around a murderous scheme to collect a rich inheritance. The object of murder is Miriam Webster, who is to share in the inheritance with her half brother Warren, who lives with his childhood guardian Helga in the mansion where Warren and Mariam grew up. Confined to a wheelchair after recently suffering a stroke, Helga is cared for by her nurse Emily, a strange young woman who has formed a close bond with Warren. Written by alfiehitchie