Former Enron executive Michael Kopper is to 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 in Houston to single charges of conspiracy to commit wire fraud and money laundering, according to two sources close to the investigation.
Kopper 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 co-operate with investigators was not immediately clear.
Kopper, who joined Enron in 1994, was never charged with wrongdoing, although he had been under investigation. One of the sources said the plea offers no guarantee that prosecutors will not seek a prison sentence for him.
Houston-based Enron created entities, called partnerships, that were largely financed by company stock and had no real value.
An internal Enron investigation concluded that some of the partnerships, created by Fastow, were used to hide debt and inflate Enron's profits by more than £670 million, misleading investors.
Federal regulators have found evidence of price manipulation and deceit by Enron as the energy trader aggressively sought ways to profit from California's volatile power markets. Prices soared in the state in 2000 and early 2001.
An investigation by Enron's board determined Kopper and his domestic partner used Enron partnerships to grow a £80,000 personal investment into £7 million in less than three years.
Government investigators are looking into whether Enron managers, from former chairman Kenneth Lay down, knew that the network of partnerships was being used to conceal huge debts.