NEW YORK (CNN/Money) - The first criminal indictment in the Enron case is expected to come Wednesday when a former executive answers charges related to the collapse of the bankrupt energy trader.

Michael Kopper is expected to plead guilty in Houston to federal charges of conspiracy to commit money laundering and conspiracy to commit wire fraud, a source told CNNfn.

Kopper worked for Andrew Fastow, the ousted Enron chief financial officer who has been called the chief architect of partnerships that helped Enron disguise debt.

Enron filed for bankruptcy protection in December after saying it vastly overstated its financial results by hiding losses. The collapse of the No. 7 U.S. company was the first of several accounting scandals that sapped investor confidence and helped pushed stocks to five-year lows.

Bryan Sierra, a spokesman for the Justice Department, declined to comment. Kopper's lawyer, Wallace Timmeny, was not immediately available for comment.

Pursuing federal charges against Enron has taken time. The former chief financial officer at WorldCom, which filled for bankruptcy in June, has already been indicted. The heads of Adelphia Communications, which went bankrupt this year, were led away in handcuffs before television cameras this summer. Former heads of Tyco International (TYC: Research, Estimates) and ImClone (IMCL: Research, Estimates) have answered criminal charges.

Kopper was called before the House Energy Committee to answer questions about the Enron collapse. But he exercised his Fifth Amendment right against self incrimination along with Fastow.

A source told the Associated Press that the plea bargain does not guarantee that prosecutors will not seek prison time for Kopper.

Kopper had run a partnership called Chewco, named for the "Star Wars" character Chewbacca, until he left Enron in 2001 to run another Fastow-created entity called LJM2, the AP reported.

Kopper, 37, is a native of Long Island, N.Y., and a 1986 graduate of Duke University. He later attended the London School of Economics and arrived at Enron in 1994, the AP said.