Washington ? Former Enron executive Michael Kopper will plead guilty to wire fraud and money laundering charges, the first admission of guilt in the federal investigation of the fallen energy giant.

Kopper, former managing director of Enron Global Finance, will enter pleas today in Houston to single charges of conspiracy to commit wire fraud and money laundering, two sources close to the investigation said Tuesday.

Kopper, 37, was a top lieutenant to ex-chief financial officer Andrew Fastow and became a focus of investigators because of his involvement in Enron-financed partnerships.

Whether Kopper’s plea was attached to an agreement to cooperate with investigators was not immediately clear.

Kopper was never charged with wrongdoing, although he had been under investigation. One of the sources said the plea offered no guarantee that prosecutors will not seek prison time for Kopper.

Houston-based Enron created entities, called partnerships, that were largely financed by company stock and had no real value. An internal Enron investigation concluded some of the partnerships, created by Fastow, were used to hide debt and inflate Enron’s profits by more than $1 billion, misleading investors.

Federal regulators have found evidence of price manipulation and deceit by Enron as the firm aggressively sought ways to profit from California’s volatile power markets.

When Enron declared bankruptcy last November, it was the largest such filing in U.S. history.

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.

An investigation by Enron’s board determined Kopper and his domestic partner used Enron partnerships to grow a $125,000 personal investment into $10.5 million in less than three years.