Elizabeth Frantz for BI

The king of ghosts

Lance Zaal is building an empire of America's undead — and making a host of enemies among the living.

Elizabeth Frantz for BI

The king of ghosts lives in a haunted $4.3 million dollar mansion in the heart of New Orleans' French quarter. The dozens of paranormal tour guides who lead tourists through the neighborhood are sure to know of him and have an opinion of him. Lance Zaal is the most controversial man in America's booming ghost business, CEO of what competitors have dubbed "The Walmart of Ghost Tours ."

Over the past half-decade, Zaal, 42, and his company, US Ghost Adventures, have opened ghost tours in more than 250 cities and towns, employing more than 1,000 guides, according to his company's website.…