R. Austin Freeman 
The Red Thumb Mark 

Originally written in 1907, „The Red Thumb Mark” opens the series by R. Austin Freeman featuring Dr. Thorndyke, who is a sort of Sherlock-Holmes type character. A single fingerprint is found at the scene of a crime. When the police are able to identify that fingerprint, the case seems closed. But Dr. Thorndyke, the detective/barrister/medical doctor who takes on defense of this suspect, thinks he can disprove the prosecution’s case, based on that same fingerprint. It does not take Dr. Thorndyke to figure out who the criminal is. It is up to Dr. John Thorndyke, and his new assistant Dr. Jervis to prove the young man’s innocence before he’s found guilty and hanged. The mystery in this wonderful detective tale is who the lovely heroine is in love with. The answer may surprise you.