Die Morde des Herrn ABC.

There's a serial killer on the loose, bent on working his way through the alphabet. And as a macabre calling card he leaves beside each victim's corpe the ABC Railway Guide open at the name of the town where the murder has taken place. Having begun with Andover, Bexhill and then Churston, there seems little chance of the murderer being caught - until he makes the crucial and vain mistake of challenging Hercule Poirot to frustrate his plans.--goodreads

The A.B.C. Murders is a work of detective fiction by British writer Agatha Christie, featuring her characters Hercule Poirot, Arthur Hastings and Chief Inspector Japp, as they contend with a series of killings by a mysterious murderer known only as "A.B.C.". The book was first published in the UK by the Collins Crime Club on 6 January 1936, sold for seven shillings and sixpence (7/6) while a US edition, published by Dodd, Mead and Company on 14 February of the same year, was priced $2.00.

The form of the novel is unusual, combining first-person narrative and third-person narrative. This approach was previously used by Agatha Christie in The Man in the Brown Suit. In The A.B.C. Murders the third-person narrative is supposedly reconstructed by the first-person narrator of the story, Arthur Hastings.

The novel was well received in the UK and the US when it was published. One reviewer said it was "a baffler of the first water," while another remarked on Christie's ingenuity in the plot] A reviewer in 1990 said it was "a classic, still fresh story, beautifully worked out."--Wikipedia