The Case of the Constant Suicides
John Dickson Carr
 Members of a large and widespread Scottish family are brought together at a highland castle in order to resolve various pieces of family business following a death. Suspicious events soon begin to occur, the body count rises, and a verdict of suicide is not necessarily to be trusted. Enter the gargantuan Doctor Gideon Fell, who applies his substantial powers of deduction to the problem of how men can be indirectly murdered while they're inside locked, sealed and inaccessible rooms.