America's First Serial Killer Designed a Murder Castle.

A footprint etched in acid helped catch a killer who admitted to being Jack the Ripper.

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HH Holmes was America’s first serial killer, in the late 1800s. More famously he is known for designing and building a murder castle where he killed many women. Although he confessed to a kill score of twenty-seven people, it is thought he could have killed as many as two hundred. It has also been suggested that he might be responsible for th…