Based on the 1918 novel. In a room locked from the inside, a millionaire is found murdered; near him are two half-burned candles.

The Malpas Mystery. Anglo-Amalgamated (British), 1960. Maureen Swanson, Allan Cuthbertson, Geoffrey Keen, Ronald Howard. Directed by Sidney Hayers. Based on The Face in the Night (1924). A girl, a former convict, and now secretary to a strange recluse, learns that she is the heir to a fortune- from her long-lost father, who is searching for her.

The Man Who Was Nobody. Anglo-Amalgamated (British), 1961. Hazel Court, John Crawford, Lisa Daniely. Directed by Montgomery Tully. Based on the 1927 novel. A girl private detective’s search for a missing playboy leads her to the mysterious “South Africa Smith.”

Clue of the New Pin. Anglo-Amalgamated (British), 1961. Paul Daneman, Bernard Archard. Directed by Davis. Based on the 1923 novel. Again, a millionaire is found killed in a locked room, the key to the door on a table near him.

The Fourth Square. Anglo-Amalgamated (British), 1961. Conrad Phillips, Natasha Parry, Delphi Lawrence, Daneman. Directed by Davis. From Four Square Jane (1928). Three valuable jewels are stolen from three London squares, with murder thrown in.

Man at the Carlton Tower. Anglo-Amalgamated (British), 1961. Maxine Audley, Lee Montague. Directed by Robert Tronson. From The Man at the Carlton (1931), the title altered so that scenes could be filmed at the newly constructed Carlton Tower Hotel. The chief suspect in a jewelry theft vanishes, his partner and the police searching for him.

Clue of the Silver Key. Anglo-Amalgamated (British), 1961. Lee (Meredith), Alexander Knox, Moira Redmond. Directed by Gerard Glaister.