Used - The ABC Murders

When Alice Asher is murdered in Andover, Hercule Poirot is already looking into the clues. Alphabetically speaking, it's one letter down, twenty-five to go.

There's a serial killer on the loose. His macabre calling card is to leave the ABC Railway Guide beside each victim's body. But if A is for Alice Asher, bludgeoned to death in Andover, and B is for Betty Bernard, strangled with her belt on the beach at Bexhill, who will then be Victim C? More importantly, why is this happening?

Often considered to be one of Agatha Christie's best.