The collapse of energy company in December 2001 precipitated what would become the most complex white-collar crime investigation in the FBI’s history.

Top officials at the Houston-based company cheated investors and enriched themselves through complex accounting gimmicks like overvaluing assets to boost cash flow and earnings statements, which made the company even more appealing to investors. When the company declared bankruptcy in December 2001, investors lost millions, prompting the FBI and other federal agencies to investigate.

The sheer magnitude of the case prompted creation of the multi-agency Enron Task Force, a unique blend of investigators and analysts from the FBI, the Internal Revenue Service-Criminal Investigation Division, the Securities and Exchange Commission, and prosecutors from the Department of Justice.

Agents conducted more than 1,800 interviews and collected more than 3,000 boxes of evidence and more than four terabytes of digitized data. More than $164 million was seized; to date about $90 million has been forfeited to help compensate victims. Twenty-two people have been convicted for their actions related to the fraud, including Enron’s chief executive officer, the president/chief operating officer, the chief financial officer, the chief accounting officer, and others.