William J. "Bill" Velardo, who oversaw the stupendous growth of Mohegan Sun and had relocated to Las Vegas three years ago, died suddenly this week.

Lynn Malerba, chairwoman of the Mohegan tribe, which owns the casino, said the tribe learned of Velardo's death through a friend. The circumstances of his passing were not immediately available.

"He was more than just an employee of the enterprise," Malerba said Wednesday. "He was the one who helped develop the culture and the core values for our employees. He tried very hard to make sure he lived those core values and that they were deep within the organization. I think that really is what made Mohegan Sun so successful."

Velardo, who was 55, left Mohegan Sun in 2006 as chief executive of the Mohegan Tribal Gaming Authority following an 11-year tenure in which the tribe's Uncasville casino became a thriving, billion-dollar corporation.

More recently, he had been president and chief operating officer of a joint venture between MGM Mirage and Kerzner International Holdings Limited to develop a multibillion-dollar integrated resort on the Las Vegas Strip. An MGM Mirage spokeswoman said that assignment ended earlier this year.