Murder Ahoy (1964)

Director: George Pollock
Cast: Charles Tingwell, Henry Oscar, Joan Benham, Lionel Jeffries, Margaret Rutherford, Nicholas Parsons, Stringer Davis, William Mervyn

Synopsis:

During an annual board of trustees meeting, one of the trustees dies. Miss Marple thinks hes been poisoned after finding a chemical on him. She sets off to investigate at the ship where he had just come from. The fourth and final film from the Miss Marple series starring Margaret Rutherford as the quirky amateur detective.