Frank Cullotta
Frank Cullotta was recruited to help run the Hole in the Wall gang by gangster Frank Spilotro before retiring the become a tour guide National Geographic

One of the most feared mobsters in Chicago and Las Vegas has reinvented himself in a bid to make a killing by more honest means - as a tour guide to his criminal haunts.

Frank Cullotta, once known as the Las Vegas Boss, was a chief in the Chicago Outfit and the Hole in the Wall gangs.

Murderer, burglar and armed robber, the 76-year-old has turned his back on his life of crime to become a tour guide in Sin City's most infamous crime spots including murder scenes and casino raids.

"It is a challenge to do things on the legal side," Cullotta told The Daily Beast.

"Sometimes the legal isn't so legal. There's graft in anything you do, even on the legal side. It's difficult to be legit, and I am legit. But I'm always having to fight the system for some reason. It seems like nobody wants me to be legit.

He said it was tough to get used to a "normal" life away from luxury at the end of a phone call.

"It's very difficult when you don't have the clout and the connections to get things done," he said. "Out there I'm like a book salesman going in and out of places. It's really rough, really hard to earn a living like that."