H.H. Holmes, born Herman Webster Mudgett, was one of America's first documented serial killers, known for his infamous "Murder Castle" in Chicago during the 1893 World's Columbian Exposition. His confession, made public in 1896, is a perplexing document that has been scrutinized and debated by historians and criminologists for over a century.

In his confession, Holmes claimed to have killed 27 people, although this number is often disputed, with some researchers suggesting it could be fewer and others proposing it might be more. The confession was sensationalized by the media of the time, with Holmes providing detailed accounts of his murders, methods of disposal of the bodies, and his motivations.

However, the veracity of Holmes' confession has been a subject of debate. Some of the people he claimed to have murdered were found alive  ...