Houston ? A guilty plea by Enron’s former accounting chief Wednesday strongly boosts the government’s conspiracy and securities fraud case against the ill-fated company’s founder, Kenneth Lay, and former chief executive officer Jeffrey Skilling, lawyers say.

Richard Causey, 45, was scheduled for trial with Lay and Skilling next month, but he came to terms with prosecutors in exchange for a promised maximum seven-year sentence. He will testify against his former co-defendants.

“This is a very, very significant win for the government,” said Philip Hilder, a former federal prosecutor who represents Enron whistleblower Sherron Watkins.

“There are very few people who can testify what may have been said in the corporate suites … and Causey is certainly one of them. As chief accounting officer, he knows where the financial skeletons are buried.”

U.S. District Judge Sim Lake accepted the guilty plea to one count of securities fraud as preparations intensified for a trial widely viewed as the climax of the Enron saga. The once highly regarded energy trading company collapsed in an accounting scandal in 2001, costing thousands their jobs and retirement savings and causing investors to lose billions.

Former Enron chief accounting officer Richard Causey walks into the federal courthouse in Houston. Causey on Wednesday pleaded guilty to one count of securities fraud and agreed to testify against former company leaders Ken Lay and Jeffrey Skilling.

Causey, who had faced 34 counts including conspiracy, wire fraud, money laundering, lying to auditors and insider trading, answered the judge’s questions in a firm, unemotional voice. He and his attorney, Reid Weingarten, declined to comment to reporters.

Attorneys for the two remaining defendants said they’re unafraid of Causey’s testimony, although they sought and won a 13-day delay in the trial until Jan. 30 to regroup.

Prosecutors – who had been bargaining with Causey’s attorneys intermittently for months – declined to comment beyond a news release outlining the deal and noting that Causey’s sentence can be reduced to five years “if he provides full, complete and truthful cooperation.”