Hulbert Footner 
Thieves’ Wit [EPUB ebook] 

A pearl necklace of substantial value has been stolen, and a novice Confidential Agent has been called in to attempt to locate them. But there is more afoot than this. A villain seeks to thwart the romance of the owner of the necklace and her fiance by framing the would-be lover and disgracing him forever in her eyes. How the persistent Detective forestalls the wicked plot makes up the story, along with a love interest of his own.