NEW YORK (CNN/Money) - Former Enron CEO and Chairman Kenneth Lay will likely be indicted this week, sources close to the investigation told CNN Monday.

While a last-minute delay was still possible, federal authorities involved with the Justice Department's Enron Task Force expect a federal grand jury next week will return an indictment of Lay, these people said, speaking on condition that they not be identified.

They would not discuss what charges might be brought against Lay. The Justice Department would not comment on the reports of a possible indictment.

Lay, 62, guided Enron for years, shaping the once-obscure pipeline company into the nation's seventh-largest corporation and a world-leading energy trading concern.

Lay's lawyer, Michael Ramsey, told Reuters the government lacked the evidence to win an indictment from a grand jury, and said an internal dispute at the Justice Department had triggered recent leaks about impending charges.

"I don't think there's going to be an indictment. I think the Task Force is leaking in order to put pressure on Washington" to seek charges, he said.

Ramsey said he met with Enron Task Force officials last week to discuss media reports that an indictment would be handed down soon, but he declined to comment on the specifics of the meeting.

Enron collapsed in a massive scandal in 2001 after the Wall Street darling's abuse of off-the-books partnerships to hide billions of dollars of debt and inflate profits became known.

Prosecutors have tapped former Enron employees for information about its inner workings, including former Chief Financial Officer Andrew Fastow, who pleaded guilty in January and agreed to cooperate with investigators in exchange for a 10-year prison sentence.

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Lay -- a political ally of President Bush and Bush's father, former President George H. W. Bush -- returned to Enron's chief executive post after Jeff Skilling resigned, shortly before the company imploded in late 2001.

Skilling pleaded not guilty in February to counts of fraud, insider trading and misrepresenting Enron's finances.

The fall of Enron touched off investigations that uncovered widespread financial fraud in corporate America and caused the high-flying energy trading industry to collapse.

The Securities and Exchange Commission also declined to comment.  

-- Reuters contributed to this report.