The Tenants of Broussac

Near Rouen, in France, stands the very ancient château of the de Broussac family. Parts of it were built as early as the eleventh century; none of it is less than two hundred years old. The family has dwindled steadily in wealth and importance until the last two generations have been reduced to living on the income derived from renting the chateau to wealthy foreigners.
Within the past year, the Chateau Broussac has had no less than six tenants; no renter has remained in possession for more than two months, and each tenancy has terminated in a tragedy of some sort.

Now the de Broussac family has commissioned Jules de Grandin to discover the reason for these problems...