The film was based on a play Without Warning by Ralph Spencer Zink which had a short run on Broadway in May 1937.[3] The New York Times called it a "competent detective play."[4]
Warner Bros bought the film rights and assigned Boris Karloff to star and John Farrow to direct. Jane Wyman was originally meant to play the female lead.[5][6]
Wyman was replaced by Marie Wilson. Filming started August 1937.[7]