Government prosecutors are trying to overcome a major legal setback in the death penalty case against Zacarias Moussaoui, the only person tried and convicted in connection with the 2001 terrorist attacks on the United States.
Moussaoui pleaded guilty last year to terrorism and conspiracy charges. It is now up to a federal jury in Alexandria, Virginia, to decide if he should be put to death, as the government wants, or sentenced to life in prison without any chance for parole.
Prosecutors are urging federal Judge Leonie Brinkema to reverse an earlier decision that bars testimony from some key government witnesses in the Moussaoui case.
Judge Brinkema barred evidence from seven prosecution witnesses after it came to light that a government lawyer had improperly coached the witnesses on their testimony.
The lawyer in question, Carla Martin, works for the Transportation Security Administration and has been placed on administrative leave.
University of Maryland law Professor Michael Greenberger says the prosecution mistake could be crucial.
"The instruction that witnesses are not to be coached or be given access to information that may bias their testimony is sort of a fundamental litigation doctrine that is well understood, both in civil and criminal cases," he said.
Prosecutors say it would be impossible to move ahead with their case against Moussaoui without the seven witnesses, who are experts on aviation security. The government is trying to show that federal aviation officials would have taken defensive actions to prevent plane hijackings prior to the 9/11 attacks if Moussaoui had told the FBI what he knew about the plot.
Moussaoui was arrested three weeks before the September 11th attacks. Although he admits to being a member of al-Qaida, Moussaoui claims he knew nothing about the 9/11 plot and that he was supposed to be part of a second wave of attacks that would target the White House.
Former federal prosecutor Tom Connolly says the judge's order barring the witnesses from testifying is a major setback for the government.
"It has just gotten half of its case thrown out. It is going to be a fatal blow to the prosecution," he said.
Judge Brinkema has said the government can still pursue the death penalty for Moussaoui, even though most of the important prosecution witnesses have now been barred.
Law Professor Michael Greenberger says the government could still prevail if the judge allows them to call one more witness who was not involved in the group coached by the government lawyer.
"So I think they had a very good chance to obtain the death penalty here," he said. "It is also a very conservative jurisdiction. It is where the Pentagon is located, the CIA is located, a lot of military live there. That is why the United States likes to bring its cases in that jurisdiction."
Some relatives of victims of the 9/11 attacks are upset about the prosecution's mistake in the Moussaoui case.
Rosemary Dillard lost her husband Eddie in the 9/11 attacks. He was aboard the plane that crashed into the Pentagon.
"I felt like my heart had been ripped out," she said. "I felt like my husband had been killed again. I felt like the government has let me down one more time."
Judge Brinkema has recessed the penalty phase of the trial until Monday.