H. H. Holmes killed people.
Herman Webster Mudgett ( May 16 , 1861 -- May 7 , 1896 ) , better known under the name of Dr. Henry Howard Holmes or more commonly H. H. Holmes , was one of the first documented serial killers in the modern sense of the term . He is commonly said to have killed as many as 200 , though this figure is traceable only to 1940s pulp magazines . Many victims were said to have been killed in a mixed-use building he owned , located about 3 mi west of the 1893 Chicago World 's Fair and said to have been a World 's Fair Hotel , though evidence suggests that the hotel portion was never truly open for business .