Israel Zangwill 
The Big Bow Mystery [EPUB ebook] 

Regarded as the first full-length locked room mystery,  
The Big Bow Mystery focuses on a murder that has occurred inside a locked room, with no clear indication as to the weapon used, the perpetrator of the horrendous crime, or a possible escape route. 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.