The Moving Finger (BBC Audio Crime)

Blurb

The Moving Finger is a detective fiction novel by Agatha Christie, first published in the US by Dodd, Mead and Company in July 1942 and in UK by the Collins Crime Club in June 1943 The US edition retailed at $2.00 and the UK edition at seven shillings and sixpence.
The Burtons, brother and sister, arrive in a small village, soon receiving an anonymous letter accusing them of being lovers, not siblings. They are not the only ones in the village to receive such letters, when a prominent resident is found murdered. This novel features the elderly detective Miss Marple in a relatively minor, deus ex machina-like role; she enters the story after the police have failed to find the murderer in the final quarter of the book, and in a handful of scenes.
The novel was well-received when it was published: "Agatha Christie is at it again, lifting the lid off delphiniums and weaving the scarlet warp all over the pastel pouffe.." One reviewer noted that "Miss Marple [is] a little old lady sleuth who doesn't seem to do much but who sets the stage for the final exposure of the murderer." Another said this was "One of the few times Christie gives short measure, and none the worse for that."