Watch American Ripper Online at Couchtuner. Herman Mudgett, alias H.H. Holmes, was America’s first serial killer. No one knows for sure how many lives he took, but it’s believed he was responsible for killing as many as 200 people in the late 19th century. A con man, opportunist and evil genius, the crowning achievement of his dark deeds was the construction of a building later dubbed the Murder Castle: a hotel on Chicago’s south side that he engineered to be a factory of death, complete with a gas chamber, dissection room, trap doors and a basement furnace to destroy any trace of his sinister work.