Another defendant, Stratis Scarlatos, withdrew his candidacy on Friday.

Judge Leonie M. Brinkema quickly rejected Mr. Moussaoui's motion, noting that under federal law a defendant may not withdraw a plea after sentencing.

At this point the defendant voluntarily withdrew from the university and went back to his job at the chemical company.

The defendant later withdrew her guilty plea and agreed to stand trial.

If the judge ultimately rejects the terms of the deal, the defendant can withdraw the plea.

The defendant withdrew the offer before receiving the acceptance, but after the acceptance was posted.

Gerard Lynch, a law professor at Columbia University, said: "A defendant can withdraw a plea for fair and just cause, but it's a tough standard to meet.

If he does not, he said, the defendants could withdraw the pleas and go to trial or maintain them and face the possibility of 10 years in prison.

By the end of last year, the defendant had withdrawn an estimated $100,000 from the family business to pay his five or six attorneys.

During the trial the defendants withdrew their previous declarations and denied any involvement.