Madeleine E. Robins 
Petty Treason [EPUB ebook] 

A lady investigator in Regency London must solve the baffling murder of a French emigre in this historical mystery.England, 1810. Once a Fallen Woman, Miss Sarah Tolerance is now an Agent of Inquiry-the sole female investigator in all of London. Her aim was to trace lost trinkets and send wastrel husbands back to their wives. But she is continually drawn into far more serious matters.Her newest case poses a puzzle unlike any she has faced before: The Chevalier d’Aubigny was beaten to death in his own bed, found by his retainers the next morning, all the doors and windows of the house sealed tight. The murder is a classic locked-room mystery, but Miss Tolerance knows she can find the key.Interviews witnesses and suspects reveal even more vexing complications-for the Chevalier had more enemies than friends, and Miss Tolerance is hard pressed to find someone who didn’t wish him dead. Her search for his killer takes her from London’s lowest brothels to the Royal Family and a Duke who must hide his dark perversions or risk the Throne.