Enter A Murderer by Ngaio Marsh
The Crime was committed on stage at the Unicorn Theatre, when an unloaded gun fired a very real bullet; the Victim was Arthur Surbonadier, an actor clawing his way to stardom using blackmail instead of talent; the Suspects included two unwilling girlfriends and several relieved blackmail victims. The stage was set for one of Chief Detective Inspector Alleyn's most baffling cases.