Who is known as America's first serial killer, infamously linked to the World's Fair?

H.H. Holmes is recognized as America's first serial killer, particularly notorious for his crimes committed during the time of the 1893 World's Columbian Exposition in Chicago. He operated a hotel, referred to as the "Murder Castle," which was designed with hidden rooms, secret passageways, and soundproofed areas intended for the purposes of murder and disposal of bodies. His heinous acts were shrouded in the excitement and chaos of the World’s Fair, allowing him to prey on unsuspecting visitors to the city.

Holmes's methods were both cunning and ruthless, as he lured numerous individuals to their demise under the guise of hospitality. His infamous modus operandi and the chilling nature of his crimes have made him a pivotal figure in criminal history, reinforcing his identity as a pioneer of serial killing in the United States.

The other figures mentioned, while notorious for their own gruesome crimes, are not connected to the World's Fair or the specific timeframe that would designate them as the first known serial killer in America.