The Red Thumb Mark

Reuben Hornby is accused of stealing diamonds from the safe of his uncle-his employer and benefactor. The sole evidence-damning evidence at that-is a paper dropped by the robber, bearing a fresh and bloody thumbprint. 

Dr. Richard Austin Freeman (born 11 April 1862-died September 28, 1943). He was a British author of detective stories, for the medico-legal forensic investigator Dr. Thorndyke. He created the confusing detective story, a crime fiction wherein the commission of the crime is portrayed toward the start, normally including the personality of the culprit, with the story, then, later describing the detective's attempt to settle the mystery. This innovation has been portrayed as Freeman's most notable contribution to investigator fiction. 30 Freeman involved some of his initial experiences as a colonial surgeon in his books. Various of Dr. Thorndyke's stories include genuine, though sometimes arcane, points of scientific knowledge from regions like tropical medicine, metallurgy, and toxicology.