Question: What is the name of the American serial killer of the 19th century on which the 1974 psychological horror novel by Robert Bloch is based?

Context paragraphs:
Exquisite Corpse (novel): Exquisite Corpse is a horror novel by American writer Poppy Z. Brite.  The protagonist of the story is Andrew Compton, an English convicted homosexual serial killer, cannibal and necrophiliac.  Brite has described it as "a necrophilic, cannibalistic, serial killer love story that explores the seamy politics of victimhood and disease."

Psycho (1960 film): Psycho is a 1960 American psychological horror film directed and produced by Alfred Hitchcock, and written by Joseph Stefano, starring Anthony Perkins, Janet Leigh, John Gavin, Vera Miles and Martin Balsam, and was based on the 1959 novel of the same name by Robert Bloch.  The film centers on the encounter between a secretary, Marion Crane (Leigh), who ends up at a secluded motel after stealing money from her employer, and the motel's disturbed owner-manager, Norman Bates (Perkins), and its aftermath.

Norma Bates (Psycho): Norma Bates (née Spool ) is a fictional character created by Robert Bloch in his 1959 novel "Psycho", and the 1960 film of the same name directed by Alfred Hitchcock and the "Psycho" franchise of remakes and sequels.  In the "Psycho" series, Norma is the deceased mother and victim of serial killer Norman Bates, who had developed a murderous split personality based on his mother.

American Gothic (novel): American Gothic is a 1974 psychological horror novel by American writer Robert Bloch, a fictionalized portrayal of real life serial killer H. H. Holmes, who is renamed "G. Gordon Gregg" for the story.

The Couch (film): The Couch is a 1962 psychological horror film directed by Owen Crump from a screenplay by Robert Bloch and a story by Blake Edwards and Owen Crump.  The film stars Grant Williams, Shirley Knight, and Onslow Stevens.  The film was released by Warner Bros. on February 21, 1962.

H. H. Holmes: 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 an American serial killer of the 19th century.

Psycho IV: The Beginning: Psycho IV: The Beginning is a 1990 American made-for-television psychological horror film directed by Mick Garris that serves as both the third sequel and a prequel to Alfred Hitchcock's "Psycho" as it includes both events after "Psycho III" while focusing on flashbacks of events that took place prior to the original film.  This is the fourth and final film in the "Psycho" series and is unrelated to Robert Bloch's third "Psycho" novel, "Psycho House", released in 1990, nor the fourth novel, "Psycho: Sanitarium", released in 2016.

Henry: Portrait of a Serial Killer: Henry: Portrait of a Serial Killer is a 1986 American psychological horror crime film directed and co-written by John McNaughton about the random crime spree of a serial killer who seemingly operates with impunity.  It stars Michael Rooker as the nomadic killer Henry, Tom Towles as Otis, a prison buddy with whom Henry is living, and Tracy Arnold as Becky, Otis's sister.  The characters of Henry and Otis are loosely based on real life serial killers Henry Lee Lucas and Ottis Toole.

David Meirhofer: David G. Meirhofer (June 8, 1949 – September 29, 1974) was an American serial killer who committed four murders in rural Montana between 1967 and 1974 — three of them children.  At the time, the Federal Bureau of Investigation was developing a new method of tracking killers called offender profiling, and Meirhofer was the first serial killer to be investigated using the technique.  Offender profiling is a method used to learn clues about the characteristics of an unknown killer from evidence at the scene of the crime and establish their behavioural patterns before they reach the height of their criminality.

Harvey Miguel Robinson: Harvey Miguel Robinson (born December 6, 1974) is an American serial killer who is a prisoner on death row in Pennsylvania.  He is one of the youngest serial killers in American history.  He was 18 years old when he was apprehended for his crimes.  He is also the first serial killer in the history of Allentown, Pennsylvania.

Supporting paragraphs: American Gothic (novel) H. H. Holmes
Answer: H. H. Holmes