Updated from 10:12 a.m. EDT

Kenneth Lay, the former Enron chief executive who was convicted in May of criminal fraud and conspiracy, died Wednesday. He was 64 years old.

Lay died of a heart attack in Aspen, Colo., according to a family spokeswoman.

"The Lays have a very large family with whom they need to communicate, and out of respect for the family we will release further details at a later time," said Kelly Kimberly, the spokeswoman.

On May 25, a federal jury convicted Lay on one count of conspiracy, two of wire fraud and three counts of securities fraud in the collapse of Enron, which he founded and led into bankruptcy in December 2001. He was scheduled to be sentenced in October.

Lay and his protege, former Enron CEO Jeff Skilling, denied wrongdoing in the scandal, which put tens of thousands of people out of work and cost many employees their life savings. Tens of billions of dollars of market capitalization was erased by the insolvency, which occurred after a series of revelations about Enron's accounting for off-balance-sheet financing tools.

Lay and Skilling faced up to 40 years in prison at a sentencing hearing scheduled for Oct. 23. Last month, prosecutors asked a judge to order both men to forfeit millions of dollars of assets, saying they were acquired fraudulently. Lay repeatedly denied he had any such assets and said throughout the trial that his net worth was negative.

During the trail, prosecutors painted Skilling as a participant in Enron's duplicity and Lay as someone willing to both conceal and profit from the company's illegal tactics.

"In late 2001, Ken Lay had a chance to prevent the outcome that happened," said John Hueston, a member of the Enron task force, following the verdict. "He had a golden opportunity to save Enron. But he made a fateful choice to place himself in front of the investors. He did that by choosing not to tell the unvarnished truth, and by not asking the hard questions."

In 1985, Enron was formed by the merger of Houston Gas Natural and InterNorth. Lay took helm of the company as CEO and over the next 15 years he built the firm into the seventh-largest publicly traded company in the U.S. By early 2001, when Skilling replaced lay in the top position, the firm's stock price had topped $90 per share.

Skilling, after only eight months at the top job, resigned as CEO, and Lay reassumed the position as the company spiraled into scandal. It filed for bankruptcy protection on Dec. 3, 2001.

Lay spent his early career years as an economist at Exxon, in the Navy and as a college professor. He was worked for a number of energy firms, including Continental Resources Co., Transco Energy and Houston Natural Gas. He also spent two years as deputy undersecretary for energy in the Department of the Interior. Born into a religious, Midwestern family, he attended the University of Missouri in Columbia and received a doctorate in economics at the University of Houston.

Despite his 40-year career as an executive and academic, he spent his last days defending his character and reputation as a Wall Street shark in federal court.

"It was an enormously difficult and stressful situation, and it took its toll," said Phil Hilder, a former federal prosecutor and the attorney for would-be Enron whistleblower Sherron Watkins.

Hilder expects that Lay's death will not have any impact on the sentencing of Skilling, and that both executives "would have been sentenced independent of one another."