The Murderer X (Spanish: El asesino X) is a 1955 Mexican crime thriller film directed by Juan Bustillo Oro and starring Carlos López Moctezuma, Manolo Fábregas and Prudencia Grifell.

[1] [2] It was shot at the Clasa Studios in Mexico City.

The film's sets were designed by the art director Javier Torres Torija.

Stylistically a film noir, it is set in the United States with a plot revolving around amnesia.

[3] This article related to a Mexican film of the 1950s is a stub.