an Entity references as follows:
Black Coffee is a play by the British crime-fiction author Agatha Christie (1890–1976) which was produced initially in 1930. The first piece that Christie wrote for the stage, it launched a successful second career for her as a playwright. In the play, a scientist discovers that someone in his household has stolen the formula for an explosive. The scientist calls Hercule Poirot to investigate, but is murdered just as Poirot arrives with Hastings and Inspector Japp.