Holmes, properly known as Herman Webster Mudgett, was America’s first mass murderer, and admitted killing twenty-seven people at his house in Chicago. He was a handsome man whose appearance made him a favourite with the ladies.

He first married in 1878 while still a student, and in 1886 contracted a bigamous marriage with Myrta Belknap. He took to fraud as a means of livelihood, and in 1888 worked in Chicago as a chemist in a drugstore. The proprietress disappeared in 1890, leaving Holmes in command of a business which thrived on sales of patent medicine.

Holmes lived in the flat above the store, sharing the premises with Icilius Conner, a jeweller, whose attractive wife Julia acted as Holmes’s secretary. Opposite the drugstore was a large vacant plot which Holmes purchased with the intention of building a hotel. The design of the Gothic-style hotel with its 100 rooms and numerous turrets and battlements was supervised by a shifty character called Benjamin F. Pitzel. Completed in 1891, the hotel, regarded locally as a monstrosity, was christened ‘Holmes’s Castle’. Hundreds of guests stayed at Holmes’s hotel, and many disappeared, including Julia Conner and her daughter.

An insurance fraud which resulted in the death of Pitzel took police to the hotel, but Holmes had fled. He was finally caught in Philadelphia and charged with embezzlement and later with murder.

When police searched Holmes’s hotel they found a veritable death house. There were airtight rooms with gas inlets and in the basement, along with the bones of several female skeletons, were vats of acid, asbestos and steel-lined, windowless rooms containing trays of surgical instruments and instruments of torture. Some of the rooms had chutes connected to upper rooms which carried human cargoes to a gruesome death below.

At Holmes’s trial in 1895, in which he conducted his own defence, a car mechanic told how he had worked for Holmes stripping flesh from bodies which he thought had come from the city mortuary. Holmes was found guilty of murder, and while awaiting execution confessed to twenty-seven killings. He was hanged at Philadelphia’s Moyamensing prison on 7 May 1896.