The Case of the Deadly Double Perry Mason : Season 1 Episode 24

When Robert Crane is charged with the murder of his sister's estranged husband Perry needs the testimony of sister Helen Reed to clear him of the charge. Unfortunately for all concerned, Helen suffers from multiple personality disorder and the second personality, Joyce Martel, is the one who is needed as the witness. Helen's psychiatrist puts her under hypnosis so Joyce can tell what she knows about the case.