Murder Ahoy on AllMovie

The last of Margaret Rutherford's "Miss Marple" films, Murder Ahoy is the only one of the series not based on an Agatha Christie original. The setting this time is a boat that has been purchased by a trusteeship to serve as a home for wayward kids. One of the trustees, Cecil Ffolly-Hardwicke (Henry Longhurst), dies while attending a meeting held aboard the boat. The police write the death off as "natural causes," but another trustee, our Miss Marple (Rutherford), suspects otherwise. Doing a little sleuthing on her own, she discovers that outwardly respectable Lionel Jeffries is using the boat as a "training school" for aspiring criminals, a la Fagin. This would seem to explain why Hardwicke was murdered, but Jeffries is much too obvious a suspect--as Miss Marple discovers nearly too late. Margaret Rutherford's husband Stringer Davis is back again as Miss Marple's platonic middle-aged friend Mr. Stringer.