The Scarlet Claw (1944)

While attending a conference in Quebec City, Sherlock Holmes and his good friend, Dr. Watson, are drawn into a murder investigation in the nearby village of La Mort Rouge. Holmes had received a letter from Lady Penrose asking for his assistance as she feared for her life. It was too late, however, as she had already been killed by the time he received it. Her throat was torn out and the local villagers are spreading rumors about monsters and evil spirits as being the cause. Holmes doesn't believe any of that and sets out to find the killer. He believes that Lady Penrose's past as an actress may have something to with her death. As others in the village are attacked, Holmes believes the killer is among them, impersonating a local villager as he goes about his business.