Herman Webster Mudgett (May 16, 1861 – May 7, 1896), better known as Dr. Henry Howard "H.H." Holmes, was an American con artist and serial killer active between 1891 and 1894. By the time of his execution in 1896, Holmes had engaged in a lengthy criminal career that included insurance fraud, forgery, swindling, three or four bigamous marriages, horse theft, and murder. Known as the Beast of Chicago, the Devil in the White City, or the Torture Doctor, his most notorious crimes took place in Chicago around the time of the World's Columbian Exposition in 1893.
Holmes was convicted and sentenced to death for the murder of Benjamin Pitezel, his accomplice in several of his cons. However, Holmes confessed to 27 murders, including those of some people who were verifiably still alive. It is believed that he also killed three of Pitezel's children, as well as three mistresses, the child of one mistress and the sister of another.