Herman Webster Mudgett (May 16, 1861 – May 7, 1896), better known as Dr. Henry Howard Holmes or H. H. Holmes, was an American con artist and multiple murderer 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 to four bigamous illegal marriages, horse theft and murder. His most notorious crimes took place in Chicago around the time of the World's Columbian Exposition in 1893.

Despite his confession of 27 murders, including some people who were verifiably still alive,Holmes was convicted and sentenced to death for only one murder, that of business partner and accomplice Benjamin Pitezel. It is believed he also killed three of Pitezel's children, as well as three mistresses, the child of one mistress and the sister of another. Holmes was hanged on May 7, 1896.