Crime and Detection: Unsolved Crimes

Despite the tireless work of crime investigators, and the wealth of modern forensic techniques available to them, a disturbing number of crimes remain unsolved. This book explores some of the most famous open cases.
Jimmy Hoffa, president of the Teamster's Union, disappeared in 1975. Although a number of suspects have been named and the influence of the Mob alleged, no one has ever been charged with his murder, and his body has never been found. The mystery of the "Black Dahlia" murder in 1947 provoked widespread speculation, and even the naming of the probable murderer, but he was found dead before the investigation could proceed. The "Zodiac" killer, who rocked San Francisco with the murder of more than 40 innocent people between 1966 and 1973, may still be at large.
So why are these cases unsolved? Often it's because the culprit cannot be identified - or, if identified, cannot be traced - or because the evidence is insufficient to bring the case to trial. Chillingly, most of these cases involve murder or suspected murder.