Title: The Champdoce Mystery
Author: Émile Gaboriau
Published: 1869
Genre: Detective

More details:

"The Champdoce Mystery" by Émile Gaboriau is a novel in the Detective genre, first published 1869.

Notes: The original French title was "Le Secret de la Maison de Champdoce". It also features an appearance by his Detective Lecoq.