R. Austin Freeman 
Savant’s Vendetta [PDF ebook] 

Humphrey Challoner had a formidable reputation in criminal anthropology. An intelligent savant devoted to science and his wife, he decides to tell the story of her tragic demise at the hands of a brutal murderer. What Challoner reveals leaves us with a feeling profound sympathy for a man who seems a victim of violent misfortune. But Challoner is not all that he seems and when he dies leaving the narrator with a rather unusual estate, a gruesome tale unfolds of venomous revenge and a perverse justice of a man driven past logic into a state of hell.