The Case With Nine Solutions (Yellowbacks)

"Mr J.J. Connington is a name revered by all specialists on detective fiction." – Spectator
When a locum doctor is called out one foggy night to a case of scarlet fever, he mistakes one house for another and discovers a young man lying in a pool of blood, who manages to choke out a dying message.
Two people are killed. "Nine solutions" are the possibility and probability combination of murder, accident and suicide that could have caused the death of these two people. This intriguing clue-laden third case for Sir Clinton Driffield has its origin in a dark scheme that reveals as much about the means for murder as its motivation. The narrowing down and elimination of the solutions to not only what could have been, but as to what it must have been is the crux of the book.