Jack L. Warner had Joan Crawford, who had just joined Warner Bros. and was looking for her first role at the studio, in mind for the role of Kathryn Mason, and sent the script for the film to her. However, after reading the script, Crawford told her agent to tell Warner that "Joan Crawford never dies in her movies, and she never ever loses her man to anyone".
The statue of the Maltese Falcon is clearly displayed as an ornament on the top of the wooden filing cabinet in Det. Lt. Egan's office when Richard visits. A few years earlier, Bogart and Greenstreet has appear in the movie about this statue, by the same name. No reference to it in the dialogue is made.