The Black Room (1935 film)

The Black Room is a 1935 mysteryhorror film, directed by Roy William Neill. The movie stars Boris Karloff in a dual role as twin brothers a doppelgnger motif. The film also features Marian Marsh and Robert Tex Allen. The film was released in Great Britain as The Black Room Mystery. The striking cinematography was done by Allen G. Siegler.

Some years later in 1834, it is revealed that the Baron Gregor Boris Karloff has become a depraved ruler who murders the wives of local peasants. His brother, Anton also played by Karloff, who cannot use his right arm and has spent much of his life traveling Europe, returns to the castle around the time of the murder, but refuses to believe the rumors he hears about Gregor. When the woman Mashka Katherine DeMille disappears after being seen with Gregor, the locals form a mob and enter the castle, confronting the baron. Gregor agrees to abdicate, and give power to his brother, who has become popular.Gregor knows that Anton will likely marry Thea Marian Marsh, niece of family advisor Colonel Hassell Thurston Hall. He lures his unsuspecting brother to the Black Room, kills him, and throws him into the pit where the dead bodies of Gregors other victims are kept. Gregor now assumes Antons identity, and prepares to wed Thea, whose lover, Lieutenant Albert Lussan Robert Allen, angrily objects. When Colonel Hassell discovers the deception, Gregor kills him. The blame for the murder is placed on Lieutenant Lussan, who is found guilty and sentenced to death. ........

Source: Wikipedia