The novel was very loosely based upon a real-life case that had made headlines, the unsolved 1920 murder of
bridge expert
Joseph Bowne Elwell. It was considered a
roman à clef because the circumstances under which Elwell's body was found—he was shot to death in a room in his home which was found to be locked from the inside, and he was not wearing his toupee—are duplicated in the novel. Modern knowledge of
ballistics reveals that one of the central premises of the novel is fanciful, because the reconstruction of the height of the murderer is impossible (
Dashiell Hammett had said as much at the time, in a 1927 book review). "The first and best, partly because Van Dine had the real-life model of the Joseph Elwell murder (1920) to hold his fancy in check." "Vance spots the murderer almost immediately but doesn't reveal him, allowing Markham and Sergeant Heath to fix the guilt on five successive persons by circumstantial evidence." ==Film adaptations==