The Twenty-One Clues

"The bodies of a worthy prelate and one of his wealthy lady parishioners are found in a bracken patch somewhat famed as a lovers' rendezvous. Torn-up love letters are scattered about. A pistol with the clergyman's finger-prints lies beside the body . . .
"If Mr. Connington says there are twenty-one clues, you can depend on it that they are offered to you as they turn up and that they will add up to the solution of the case. Mr. Connington has been aptly termed 'the modern master of pure detection.' Can you fit together the pieces of his latest fascinating mosaic of death? Can you beat Sir Clinton Driffield to the solution?"
"The Twenty-One Clues" was published in 1941.