A medical jurist receives an urgent call to assist in a murder investigation. The victim, Alfred Hartridge, is found dead in his chambers, stabbed with a dagger that remains embedded in his back. The circumstances surrounding the murder are perplexing, as the door was bolted from the inside, and there are no apparent means for the murderer to have escaped. Henry Curtis, the victim's brother-in-law, seeks help from the jurist and his colleague, Dr. Thorndyke. Curtis reveals that he had a contentious relationship with Hartridge, who had been uncooperative regarding financial support for Curtis's family. The police, led by Inspector Badger, are present at the scene, and they begin to piece together the events leading to the murder. The investigation reveals that Hartridge was last seen alive by Curtis and his solicitor, Mr. Marchmont, who had accompanied him to confront Hartridge about financial matters. The police discover that Hartridge had received threatening letters, hinting at a vendetta against him. The letters are traced back to a group of Italians who had been loitering outside the building, but their involvement remains unclear. Thorndyke meticulously examines the crime scene, taking photographs and measurements. He notes peculiarities about the dagger, including its lightweight aluminum hilt and the engraving of the word "Traditore," meaning "traitor." The investigation leads to the discovery of a connection between Hartridge and a man named Leonard Wolfe, who stands to inherit Hartridge's estate. As the investigation unfolds, Curtis's daughter, Edith, is arrested for the murder due to circumstantial evidence, including her left-handedness, which matches the profile of the murderer. However, Thorndyke believes that the true murderer is still at large and focuses on the peculiarities of the crime. Thorndyke's deductions lead him to suspect that the dagger was not used in a traditional manner but was instead fired from a compressed-air rifle, a theory he tests successfully. He identifies Wolfe as the likely murderer, who had a motive to eliminate Hartridge to secure his inheritance. The investigation culminates in Wolfe's arrest, but he takes his own life before facing trial. The case highlights the complexities of criminal investigation, the importance of attention to detail, and the potential for clever criminals to mislead authorities. Thorndyke's analytical approach ultimately uncovers the truth, demonstrating the effectiveness of forensic science in solving crimes.
By R. Austin Freeman · First published 1931 · Genre: Mystery, Crime, Detective Fiction