A federal prosecutor in the death penalty trial of Zacarias Moussaoui told the judge in the case that he saw "no point" in going ahead with the proceedings under a ruling that barred key government witnesses from testifying.

Assistant U.S. Attorney Robert A. Spencer, one of the prosecutors trying to persuade a jury that Moussaoui deserves the death penalty for his role in the Sept. 11, 2001, terrorist attacks, made the comment in a conference call yesterday among U.S. District Judge Leonie M. Brinkema and lawyers for the prosecution and defense after Brinkema prohibited testimony and evidence from half a dozen federal aviation witnesses. Brinkema issued the ruling after a day-long hearing convinced her that misconduct by a federal lawyer had so tainted the proceeding that all evidence concerning aviation security must be stricken.

The decision gutted the case that prosecutors were building in their attempt to have Moussaoui executed for the attacks on the World Trade Center and Pentagon. Moussaoui, 37, a French citizen of Moroccan descent, pleaded guilty last April to six conspiracy counts related to the Sept. 11 attacks. If the death penalty trial does not go forward or if the jury ultimately decides in favor of the defense, Moussaoui would be sentenced to life in prison without parole.

The prosecution is considering an appeal of Brinkema's decision to bar the key witnesses, but it was not immediately clear whether such an appeal could be filed while the trial is underway.

In the conference call, held to discuss the prosecution's request for a delay in the trial until Monday, Spencer agreed with Brinkema that other government witnesses could still testify.

"But we don't know whether it is worth us proceeding at all, candidly, under the ruling you made today, and that's why we need to assess it, because without some relief, frankly, I think that there's no point for us to go forward," Spencer said.

He suggested that resuming the trial under current conditions could just "waste the jury's time and the court's time."

Defense attorney Edward B. MacMahon Jr. objected to the postponement, saying he did not think the prosecution had legal grounds to appeal Brinkema's ruling since Moussaoui already "has been put in jeopardy."

Brinkema said she was not sure that the type of appeal being contemplated by the prosecution had come up in her court before "in the middle of a trial." But she granted the prosecution's request for a postponement, ordering that the penalty trial resume Monday at 9:30 a.m.

A court transcript of the conference call was released last night.

Legal experts said yesterday that Brinkema's ruling devastated the prosecution's main argument -- that if Moussaoui had not lied to the FBI about his knowledge of the Sept. 11 plot when he was arrested on an immigration charge in August 2001, the hijackings could have been prevented. The witnesses are airline security experts who would have testified about the measures the government would have taken had the truth been told.

Brinkema issued her ruling at the close of an extraordinary hearing in Alexandria that centered on the conduct of Carla J. Martin, 51, a Transportation Security Administration lawyer who improperly shared testimony and communicated with seven witnesses. New evidence emerged that Martin was heavily involved in the case and had committed what Brinkema called other "egregious errors."

The most serious was telling a prosecutor that witnesses sought by defense attorneys had refused to meet with them. Relying on Martin's contact with the witnesses, prosecutor David J. Novak relayed the information to the defense. After hearing from those witnesses yesterday, Brinkema called Martin's information "a bald-faced lie."

"I cannot allow that kind of conduct to go without there being serious sanctions," Brinkema said as she struck the expected testimony and all of the evidence about aviation. "It would likely turn the criminal justice system on its head."

The judge placed Martin's conduct, combined with other errors in the oft-delayed case, in historic terms. "I don't think in the annals of criminal law there has ever been a case with this many significant problems," she told a packed courtroom.

Some families of Sept. 11 victims were shaken by the decision. Rosemary Dillard of Alexandria, whose husband, Eddie, died on the flight that hit the Pentagon, said she didn't blame Brinkema but is grieving all over again.

"It's like they ripped the sore off, and it's getting deeper and deeper, and I'm going to be right back where I started," she said.

Yesterday's hearing featured only a brief appearance by the woman at the center of the controversy. Brinkema warned Martin that she could be held in criminal or civil contempt. In an unusual move, the judge read Martin a version of the Miranda warning given by police to criminal suspects as she took the stand at the start of the hearing.

Speaking agitatedly, Martin said she "very much" wanted to testify but that it was an "adversarial proceeding" and that she needed a lawyer. With that, Martin left the courtroom and did not return. Her attorney, Roscoe C. Howard Jr., later told the judge that Martin would not be available to testify. Howard, a former U.S. attorney in the District, declined to comment.

Although Brinkema declined defense requests to throw out the death penalty, prosecutors must decide whether to proceed with a stripped-down case or appeal her ruling.

Government sources said the most likely next step would be a motion to Brinkema to reconsider her decision.

Justice Department spokeswoman Tasia Scolinos said lawyers are reviewing Brinkema's ruling. She called it "disappointing, especially given the quick actions taken by Justice Department lawyers to report the misconduct, which occurred without the knowledge of the prosecutors." But, Scolinos said, "Moussaoui faces at a minimum life in prison without the possibility of parole."

Michael Greenberger, a former Justice Department official who heads the Center for Health and Homeland Security at the University of Maryland, said the government's case has "exploded in its hands" through "unbelievable bungling. . . . I place the responsibility on the prosecutors. It's sort of prosecution 101 that you keep the lawyers who are helping you under control."

But Eric H. Holder Jr., who was deputy attorney general in the Clinton administration, said the prosecutors can't be blamed for placing their faith in Martin, a veteran lawyer who is an expert on aviation security. "At some point, you have to be able to believe that a colleague is giving you the straight scoop," he said.

Because Martin didn't testify yesterday, it was impossible to determine why she violated Brinkema's order. She did not return calls to her home or answer the door at her apartment.

Friends and former colleagues said she was a career Federal Aviation Administration attorney who moved to the new TSA in 2002 largely because of her work on the case of the Pan Am Flight 103 explosion in 1988 over Lockerbie, Scotland. Martin represented the government at a civil trial in which victims' families sued the airline. She was there to make sure that sensitive information was not discussed in open court.

In the Moussaoui case, her name appears on some court documents that are specific to aviation security.

Martin graduated from the University of Tennessee and went to law school at American University, beginning to practice in 1990. She was a flight attendant for several years before she went to law school, said Gary W. Allen, who knew Martin when he supervised aviation litigation at the Justice Department.

The problems that triggered yesterday's hearing emerged Monday, when prosecutors informed Brinkema that Martin had violated a court order by e-mailing trial transcripts to the seven witnesses -- all current and former federal aviation employees -- and coaching them on their testimony. Brinkema had ruled that most witnesses could not attend or follow the trial and could not read transcripts.

Martin's e-mails criticized the prosecution, saying its opening statement "has created a credibility gap that the defense can drive a truck through." She questioned an assertion by prosecutors that the government could have stopped the Sept. 11 attacks by taking steps such as having the FAA focus airport security on short-bladed knives. The Sept. 11 hijackers used such knives to take over four airplanes.

Lynne Osmus, the FAA's assistant administrator for security and hazardous materials, testified yesterday that she reported Martin's e-mails to prosecutors Friday because she thought they were "an odd communication."

Asked by defense attorney MacMahon whether it alarmed her that Martin wrote in one e-mail "please don't respond," Osmus said: "Yes, it did. I didn't want to have secret discussions with her."

Osmus and the four other senior FAA and TSA officials who testified yesterday said their communication with Martin would not have affected the testimony they would have given. Osmus's deputy, Claudio Manno, said he brushed aside Martin's e-mails "because I can only testify about what I know."

The witnesses portrayed Martin as an obsessive lawyer who e-mailed them repeatedly -- and called them over the weekend after prosecutors began investigating her conduct. Only then did she tell them not to read her earlier e-mails and to stop following news coverage of the trial, they said.

"Ms. Martin sometimes had a tendency to go off on tangents that were not all that relevant, and it was really taking up a lot of time," Manno testified.

He said Martin, who had been the liaison between the prosecution team and aviation witnesses, was replaced last week at the request of Osmus, Manno and other officials.

As the hearing wore on, it became clear that Martin was extensively involved in key portions of the government's case. She helped prepare witnesses and coordinated searches for documents, some of them classified.

"Her involvement in that portion of the case so taints everything she touched," Brinkema said. "How can any rational trier of fact rely on any representation she had made?''

Staff writers Michael Laris, Carol Morello, Paul Schwartzman and Ian Shapira and staff researcher Bobbye Pratt contributed to this report.

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