Many censors cut parts of the death scenes of the woman (Arlene Francis) of the streets - eliminating her stabbing and being tied to the cross beams.
Among the caricatures drawn on the walls of Dupin's apartment is the likeness of Edgar Allan Poe, who wrote the story the film is based on.
Universal replaced Robert Florey from directing Frankenstein (1931) (for which Bela Lugosi did a screen test) with James Whale. Boris Karloff replaced Lugosi in the film and played the monster. As compensation, Universal Pictures assigned the director and Bela Lugosi to this film.
The running time of this film was originally 80 minutes. The many violent sequences in it caused Universal to cut its running time to 61 minutes.
In Edgar Allan Poe's short stories, C. Auguste Dupin is a man in Paris who solves the mystery of the brutal murders, not Pierre Dupin. Dupin appeared in three of Poe's short stories, "The Murders of the Rue Morgue", "The Mystery of Marie Rogêt" and "The Purloined Letter".