Late 19th-century London is plagued by a serial murderer targeting only local constables. And when the latest victim is found near an upscale party where a charming thief (Peter Lawford) has just masterfully lifted a precious emerald from its owner, Scotland Yard becomes convinced that the crimes are linked. Now, Lawford must try to trap the real killer if he hopes to prove his innocence. Dawn Addams, Roland Culver co-star; based on a novel by Philip MacDonald. 80 min. Standard; Soundtrack: English Dolby Digital mono.