H. H. Holmes was one America's first documented serial killers documented. He was hanged for the murder of his business partner. While nine victims were forensically proven, Holmes claimed to have killed 27 people.
Holmes in the Timeless Universe
The World's Fair Hotel in Chicago of 1893, the hotel built by H. H. Holmes, was full of death traps, such as trapdoors, acid vats, and torture racks. Garcia Flynn tricks Wyatt Logan and Rufus Carlin into going to this hotel. In the hotel, Wyatt, Rufus, Sophia Hayden, and H. H. Holmes, under the alias George Henry, get knocked unconscious with gas and trapped inside one of the isolation chambers.
Later, when everyone in the chamber wakes up, Hayden determines the chamber is soundproof and airtight. Holmes offers Rufus a box of Cracker Jacks.
Wyatt assures the people in the isolation chamber that they will escape and reunite with their families. Hayden finds a spalling brick which Wyatt is able to make a hole in. He cries for help, and Lucy Preston and Harry Houdini hear the cry and rescue Wyatt, Rufus, Hayden, and Holmes.
Wyatt and Lucy begin to search for H. H. Holmes. Wyatt forces the hotel's caretaker, Pat Quinlan, to lead Wyatt to Holmes when Lucy discovers through a photograph that George Henry is H. H. Holmes.
Lucy is abducted and trapped by Holmes. Worried about being found out by the authorities, Holmes tries to kill both himself and Lucy, but Lucy uses her knowledge of history to make Holmes think she is a psychic. Wyatt and Rufus find where Holmes had Lucy hidden. Holmes, in an attempt to defend himself, says that if Wyatt doesn't kill him, that he'll tell the families of all his victims what he did to them to give their families closure. Lucy confirms that H. H. Holmes never does anything like this in the original timeline. Wyatt shoots H. H. Holmes to death.
H. H. Holmes at Wikipedia