The ABC Murders (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…