Kevin Stoney is dubbed by another actor.
Stringer Davis, who plays Miss Marple's friend Mr. Stringer, was actually Margaret Rutherford's husband. The part of Mr. Stringer was created for him.
As in the previous film, Murder She Said, the gruff general factotum is again named Hillman.
Like Murder Most Foul, this movie was adapted from a Poirot novel, not a Miss Marple novel.
Miss J.T.V. Marple earned her Junior Silver Spurs at Brockbrook in 1910; she retained her mother's vintage 1885 Broadbreech side-saddle.
Miss Marple refers to a "remarkable novel" of Agatha Christie's, "The Ninth Life". This was an in-joke; her creator wrote no such book.
The world première took place at a church garden party in rural Cheshire, England.
When reporting the second murder to the police on the phone, Miss Marple uses the phrase "Murder most foul". A quote from William Shakespeare's "Hamlet", it was reused as the title of the following Miss Marple movie.