The Haunted Strangler

Boris Karloff plays James Rankin, a researcher investigating a notorious serial killer who was hanged 20 years earlier seemingly becomes possessed by the long dead strangler. The case starts to consume him, literally... Rankin's investigation leads him to suspect that Dr. Tennant, a regular patron at the Judas Hole music hall where one of the Strangler's victims died, may be the real killer. As he delves deeper, Rankin undergoes a transformation that contorts his face and paralyzes his left arm, revealing his true identity as the Strangler.