The Jade Mask (1945)

Eccentric scientist Harper lives in a spooky mansion with all the trimmings: hidden lab, secret panels, inscrutable butler, and greedy relatives with unusual talents. When Harper seems to be murdered, Charlie Chan (with the uninvited help of No. 4 son) tries to answer such questions as Where's the body? How can a dead man walk? And how can a secret murder be done in full view of detectives and witnesses?