During the scene where Echo and company are fleeing the pet store, Echo decides to take his pet ape with them. The "ape" was actually a three-foot-tall chimp who was made to appear gigantic with camera trickery, a specially built smaller-scale set to make it look bigger, and perspective shots. When Echo removes the ape from his cage, the shot shows Echo (with his back turned to the camera) unlocking the cage and walking the ape to the truck. The ape appears to be roughly the same size as Echo. This effect was achieved by having dwarf actor Harry Earles (who played "Tweedledee" in the film) play Echo for these brief shots, and then cutting to the normal-sized Lon Chaney, making it seem as though the ape is gigantic.
There was a scene in which Tweedledee murders a young child during a botched robbery. Tod Browning cut the scene from the final version, concerned it would be too disturbing.
While getting ready for the role, Lon Chaney remembered a thief he met when he traveled in his youth. He borrowed the man's attitude and mannerism.
In the original novel by Clarence Aaron 'Tod' Robbins, Tweedledee is the mastermind of the Unholy Three instead of Echo.
The film was remade as a talkie, Le club des trois (1930), also starring Lon Chaney and Harry Earles. For the former, the remake was his only talkie picture.