Enron Corp's former chief accountant agreed to plead guilty on Tuesday to criminal conduct that preceded the energy giant's collapse into bankruptcy, sealing a deal that would give prosecutors another key witness against former chief executives Kenneth L Lay and Jeffrey K Skilling.

Richard A Causey, who is facing more than two-dozen criminal charges, is scheduled to appear in a Houston courtroom on Wednesday, according to court records.

The Enron Saga

He reported directly to Skilling for years and participated with former executive Lay on conference calls and analyst meetings in the weeks before Enron fell apart.

All three men had been scheduled to face trial on January 17, and the trio long had presented a united front. But eleventh hour negotiations with the Justice Department's Enron Task Force and the prospect of spending decades behind bars led him to enter the plea deal, sources told The Washington Post.

The deal comes at a crucial time for Lay and Skilling, who are charged with leading a conspiracy to defraud investors by hiding debt and inflating profits at the Houston energy trading firm before its December 2001 collapse.

They are the last and among the most eminent corporate executives to face trial in an era of scandal dating to the 1990s.

Defense lawyers for Lay and Skilling are almost certain to seek a delay in the trial because of Causey's plea deal, the 16th by a former Enron executive, the report said.