Carla Martin has been told to show up at U.S. District Court in Alexandria on Monday morning, said the sources, who requested anonymity because the hearing has not yet been publicly disclosed. It is unclear if Martin will testify or what she might say.

Martin's actions halted testimony in Moussaoui's death penalty trial last week after she violated a court order by sharing testimony and contacting witnesses. U.S. District Judge Leonie Brinkema initially reacted by barring all aviation evidence and witnesses from the case. The aviation evidence is crucial to prosecutors, who are arguing for the execution of the only person convicted in the United States on charges stemming from the Sept. 11, 2001, terrorist attacks.

Brinkema later relented and allowed prosecutors to present aviation security experts untainted by contact with Martin.

Martin, a Transportation Security Administration lawyer who has been placed on paid leave by TSA, has not commented publicly. Her lawyer, Roscoe Howard Jr., has said she has been ''vilified'' by prosecutors and the media and intends to mount a defense.

Brinkema is now expected to consider a motion from Moussaoui's defense team asking that she throw out the case and not let it go to the jury.

If Brinkema allows the trial to continue, the defense case would begin and Moussaoui would have a constitutional right to testify. Moussaoui has long been known for courtroom outbursts, but he has sat quietly for most of the trial, only yelling things such as ''God curse America'' when jurors and Brinkema are out of the courtroom.