Classicly

The Big Bow Mystery is an early locked-room mystery novel written by British novelist Israel Zangwill, who was a close associate of Theodor Herzl. 

A man is horribly murdered in his bedroom, the door locked and bolted on the inside. Scotland Yard is stumped. Yet the seemingly unsolvable case has, as Inspector Grodman says, "one sublimely simple solution" that is revealed in a final chapter full of revelations and a shocking denouement.