NEW YORK (CNN/Money) - Former Enron Corp. executive Michael Kopper (more about Michael Kopper) pled guilty Wednesday to fraud charges and agreed to help investigators, likely setting the stage for more indictments related to the bankrupt energy trader's collapse.

Kopper pled guilty in Houston to federal charges of conspiracy to commit money laundering and conspiracy to commit wire fraud, the first charges brought in the high-profile Enron case.

AP photo

Kopper agreed to cooperate with prosecutors and pay $12 million in restitution as part of a plea-bargain deal. He was released on $5 million bail.

"This plea marks a significant milestone in the Enron investigation," Deputy Attorney General Larry Thompson said in a press conference. "We have secured the cooperation of an important witness, and...today's plea allows us to collect an additional $12 million to go to the relief of Enron investors."

After Kopper made his plea, the Securities and Exchange Commission said it had also filed and settled civil charges against him, though Kopper did not admit or deny the SEC charges.

As part of his bargain with the Justice Department and the SEC, Kopper will be barred from serving as an officer or director of a public U.S. company.

Michael Kopper, a former Enron executive, pleads guilty to fraud charges in the Enron case and is released on $5 million bail. CNN's Ed Lavandera reports from Houston. Play video

The SEC will handle the distribution of the $12 million, though it hasn't yet determined how it will disburse the money. Justice officials said the department had identified about $23 million in additional assets, belonging to former Enron chief financial officer Andrew Fastow and other company executives, that it hoped to recover.

The plea agreement must be approved by a federal judge, who will also have the discretion of sentencing Kopper to prison time. Kopper faces a total sentence of up to 15 years.

The Justice Department said it would make no recommendation to the judge about whether or not Kopper should be sentenced, though they would inform the judge of Kopper's cooperation. Officials with both Justice and the SEC expressed optimism about the amount of information Kopper would give them.

RELATED DOCUMENTS       Cooperation Agreement (US v. Kopper) Complaint (S.E.C. v. Kopper) Criminal Information (US v. Kopper)

"We anticipate that the cooperation Mr. Kopper has agreed to provide will be important in identifying fully the individuals and entities that contributed to the company's collapse," SEC Enforcement Division Director Stephen Cutler said in a statement.

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

The criminal and civil charges accused Kopper of being involved in three transactions, called RADR, Chewco and Southampton, that allegedly helped Enron hide the true nature of its assets and liabilities.

The charges also claimed that Kopper, Fastow and others used the partnerships to misappropriate millions of dollars in undisclosed fees and illegal profits.

Fastow spokesman Gordon Andrew would not comment on the charges. Fastow and Kopper had been called before the House Energy and Commerce Committee to answer questions about the Enron collapse, but both exercised their Fifth Amendment right against self-incrimination.

After the plea, Kopper's attorney said, "Michael has admitted he misused his position at Enron to enrich himself and others and in so doing violated his duties as an Enron emplyee."

Enron filed for bankruptcy protection in December after saying it had 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 push stocks to five-year lows.

Last week, Sen. Byron Dorgan, D-N.D., chairman of the Senate Commerce subcommittee on consumer affairs, complained about the slow pace of the Enron investigation. He noted that executives from other companies, including bankrupt WorldCom, Adelphia Communications, Tyco International (TYC: Research, Estimates) and ImClone (IMCL: Research, Estimates), had already been indicted.

Though pursuing federal charges against Enron and its former executives has been a somewhat laborious process, Thompson said the investigation was "active and ongoing" and that he was pleased with its progress.

"I think the American people would want the Department of Justice to conduct an investigation that is thorough and that produces charges that are sustainable in a court of law," he said.

Federal prosecutors have obtained convictions against former Enron auditor Arthur Andersen and a former Andersen executive, David Duncan.

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, where he finished in the bottom fifth of his accounting class. After a brief stint at Toronto Dominion Bank, he joined Enron in 1994.