Death on the Nile (Hercule Poirot, #18)

by Agatha Christie

Poirot said: “It will be simpler to say who it could not have been. Neither Monsieur Doyle, Madame Allerton, Monsieur Allerton, Mademoiselle Van Schuyler, nor Mademoiselle Bowers could have had anything to do with it.