Bela Lugosi stars as some weirdo mad scientist/carney who goes around murdering young women by injecting them with the blood of his pet ape. Meanwhile, some amateur sleuth type tries to solve the mystery, which is a little uninvolving and ultimately anticlimactic considering the fact that the film openly tells you who the killer is and what he's doing from the beginning.
On Thursday night I watched a trio of films from the 1930's starring Bela Lugosi that were (loosely) based on Poe stories. (Two of them also starred Boris Karloff!) I can't say I was particularly enamoured with any of them, but each one did have certain merits and charms. Other than some effectively moody cinematography, I think the most memorable aspect of Murders in the Rue morgue is the ape, particularly his death scene (shot at close range, knocked off the rooftop and into the canal below).