The glenlitten murder (E. Phillips Oppenheim)

Glenlitten Manor is the home of Andrew, Marquis Glenlitten, and his lovely, tiny, vivacious French wife, Felice. On the night of a small game hunt, the unsavory Baron de Bresset is murdered and the priceless Glenlitten diamond is stolen. Who stole the necklace and killed de Bresset? The subplot around the origins of Felice, who was orphaned in a French chateau at a very young age, form an interesting side story. Suspects include Sir Richard Cotton, the famous London criminal lawyer, Sir Richard Haslam, the African colonial administrator, and Prince Charles de Seuss, the impoverished Russian nobleman. Very formulaic, with some interesting descriptions of English country house life just prior to the Great Depression.