Herman Webster Mudgett, better known as H. H. Holmes, was born on May 16, 1861, in Gilmanton, New Hampshire. He was the third child of Levi Horton Mudgett and Theodate Page Price. Both of his parents came from families that were among the first English settlers in the area. His father, Levi, worked as a farmer, trader, and house painter. He was known to be a heavy drinker and reportedly mistreated his family. Holmes's mother, Theodate, and their household were deep-rooted in the Methodist faith.

As a child, Holmes was highly intelligent. He excelled in school and faced bullying from his classmates because of his academic abilities. In high school, he attended Phillips Exeter Academy and later graduated with honors from Gilmanton Academy at the age of 16. During his adolescence, he encountered a frightening experience when other students forced him to stand in front of a human skeleton. While initially terrified, he grew fascinated by the skeleton and developed a lifelong obsession with death and dissection.

In 1879, Holmes enrolled at the University of Vermont. However, he only stayed for one year before transferring to the University of Michigan's Department of Medicine and Surgery in 1882. He graduated in June 1884 despite having mediocre grades. While in medical school, he worked in the anatomy lab under Professor William James Herdman. They were involved in graverobbing to supply cadavers for medical study. Before enrolling at the university, Holmes had also apprenticed under Nahum Wight in New Hampshire, who was known for advocating human dissection.

Herman Webster Mudgett, better known as H. H. Holmes, was a serial killer active primarily in the late 19th century. He is suspected of committing many murders, with confirmed killings of some known individuals.

Holmes's murder spree is believed to have started around 1880 when he was still using his real name. One of his earliest presumed victims was a train conductor named William C. Burmann, whose identity Holmes allegedly stole. As he moved to Chicago in 1886, Holmes began using the name "H. H. Holmes" and quickly engaged in many shady practices, including running a drugstore and constructing a large building often referred to as his "Murder Castle."

He was involved with several women, including Julia Smythe, a mistress who vanished along with her daughter, Pearl, on Christmas Eve of 1891. Holmes provided several conflicting stories regarding their disappearances. He later claimed that Julia died during an abortion and that he poisoned Pearl to cover up the truth.

Another victim was Emeline Cigrand, who worked for Holmes and disappeared in December 1892. Her empty luggage was returned to her family, while her remains were later found as part of a skeleton linked to another case. Holmes also had relationships with Wilhelmina "Minnie" Williams and her sister, Anna, both of whom disappeared in 1893.

After committing various murders, Holmes's most notorious actions involved the Pitezel family. Benjamin Pitezel, a man involved in several of Holmes's schemes, was murdered in September 1894 under a false plan to fake his own death. Following Benjamin's death, Holmes took three of Pitezel's children into his custody, eventually murdering them as well. The girls Alice and Nellie were killed in October 1894, while their brother Howard met a similar fate shortly after.

Holmes was captured on November 17, 1894, and evidence from the Pitezel case led to his trial. He was convicted of Benjamin Pitezel's murder in October 1895 and sentenced to death. In prison, he confessed to killing 27 people, although many of these claims were viewed with skepticism.

On May 7, 1896, Holmes was executed by hanging.