Erford Gage, who played the poet Jason Hoag, enlisted in the U.S. Army in August 1943 (around the time this film was released) and was killed in action in the Phillipines in March 1945.
The character of Mimi, the dying prostitute, comes from the opera "La Bohème" by Giacomo Puccini. References such as this are common in Val Lewton's films.
The original story for the film (outlined by DeWitt Bodeen) was to be about an orphaned heroine caught in a web of murder against a background of the Signal Hills oil wells. If she didn't find out the killer's identity in time, she would become his seventh victim. Producer Val Lewton wanted the story to go in a different direction and called in a second writer to help reshape it.
Tom Conway recreates his character of Dr. Judd from Cat People (1942). In memos and early drafts of the script, Conway's character was referred to as "Mr. Siegfried". Film scholars believe that the character's name was changed to provide continuity between the two films, and to capitalize on Cat People's success. Judd's character, however, had died in Cat People, calling into question the relation of the two fictional narratives.