The Strangler of Blackmoor Castle

A hooded killer invades the Blackmoor estate, assaulting Lucius Clark and demanding the return of stolen diamonds. The phantom leaves behind a gruesome calling card - the murdered body of a groundskeeper, with the letter "M" marked on his forehead. An inspector arrives from Scotland Yard to catch the strangler and concludes that the murders are the work of a man with nine fingers. Clark's paranoia leads him to accuse his friends and servants. The case is at a standstill when two more disfigured corpses are discovered, but a parcel of hidden love letters provides the investigator with the clue he needs to pick up the trail of the strangler. A violent confrontation with the killer leads to the exposure of false identities and an uncovering of long-buried secrets.

Director Harald Reinl was chosen to continue directing the Dr. Mabuse films of the 1960's after Fritz Lang's retirement, and this influence can be seen in the sweeping, heavily-contrasted world of The Strangler of Blackmoor Castle. The suspenseful, well-crafted story is complemented by a brilliant electronic soundtrack by avant-garde musician Oskar Sala, who composed the score for Hitchcock's The Birds in the same year.