Like most of Christie’s novels and short stories, “The Witness for the Prosecution” is best described as a mystery: The story centers on an unsolved murder, and as a solicitor, Mr. Mayherne plays a role comparable to that of a detective, conducting client interviews and researching the details of the case (in the British legal system, this kind of work is traditionally performed by a solicitor who then hands the case over to a barrister to argue in court). However, the story also departs from Christie’s usual formula in a number of key ways, beginning with the fact that it centers on a murder that has already happened, rather than one that takes place within the narrative itself. Relatedly, for most of the story, the primary source of tension is not the question of who killed Miss French, but whether Vole (whom Mayherne incorrectly believes to be innocent) will be wrongfully convicted, and why Romaine seems so determined to see him executed.

As it turns out, both of these questions are misdirected: Vole is guilty, and Romaine is actually exceptionally devoted to him, to the extent that she exposes herself to charges of perjury on his behalf.