The ABC Murders by Agatha Christie

Murder is a very simple crime. As easy as ABC.
 
The whole country is in a state of panic. There is a killer on the loose, growing more confident with each successive execution – Alice Ascher in Andover, Betty Barnard in Bexhill, Sir Carmichael Clarke in Churston – laying a trail of deliberate clues to haunt the world’s greatest detective, Hercule Poirot. Which might just be the killer’s first mistake…