Often considered a sub-genre of the crime and mystery genres, the whodunit play is a thrilling plot-driven detective story. Suspenseful throughout, the aim of a whodunit is to discover who committed the murder? The audience normally witnesses the perfect crime, while suspects are then wrongly accused. Agatha Christie’s whodunit The Mousetrap ran continuously on London’s West End from 1952 to 2020, making it the longest first run of any play in history. J. B . Priestley’s play An Inspector Calls (1945) is another fine example of the genre.