A federal jury yesterday convicted former Air Force intelligence analyst Brian P. Regan on three charges of attempted espionage, acquitted him on a fourth and said it could not agree on whether his spying should make him eligible for the death penalty. The panel was ordered to resume deliberation on that question Monday morning.

The 12-member jury found Regan guilty of trying to sell classified documents to Iraq and China and of breaking the law against gathering national defense information. Jurors rejected government arguments that Regan also tried to sell classified material to Libya, one of two counts that carried a possible death penalty. The Iraq charge was the other count punishable by death.

In a dramatic turn to a controversial case, jurors told the judge that Regan was guilty on the Iraq spying charge but said they disagreed over whether the crime met legal standards required to make him eligible for capital punishment. U.S. District Judge Gerald Bruce Lee sent the jurors home and ordered them to return Monday.

The split finding raised the possibility that the jury that convicted Regan of trying to sell secrets to Saddam Hussein could ultimately deadlock on whether he should be eligible to die for it. If that happens, several legal specialists said, it is unclear whether the conviction on the Iraq count would stand but without the death penalty, or whether a new trial would be held on that charge.

Lee, however, said he hoped more deliberations would avoid the prospect of a deadlocked jury on the Iraq charge. "They have not reached the conclusion that they are hung, but it sounds like they are struggling to reach unanimity in answering that question," he said in court.

To make Regan eligible for the death penalty on the Iraq count -- which would make him the first espionage defendant to face execution in the United States in half a century -- jurors would have to mark "yes" to a second question on the verdict form. It asks whether the attempted espionage concerned at least one of a variety of weapons systems, such as nuclear weaponry or military satellites.

Prosecutors portrayed the guilty verdicts as a clear victory, pointing out that Regan faces up to life in prison for his crimes.

"Today is an important victory for the American people," Paul J. McNulty, the U.S. attorney in Alexandria, said in a statement. "This conviction demonstrates that traitors can and will be held accountable."

But defense lawyers and other legal specialists not involved in the case took a different view, saying the uncertainty of whether there will be a death penalty phase to the trial shows that the government should not have sought capital punishment in the first place.

Regan's attorneys had argued vehemently that he should not face the death penalty because far more renowned spies did not. Even some government officials have privately voiced disagreement with the Justice Department's decision to seek capital punishment, which comes as Attorney General John D. Ashcroft is pushing federal prosecutors across the country to seek death penalties in a variety of cases.

"It's a wonderful result for the defense," said Barry Boss, a Washington defense lawyer who has defended federal death penalty cases. "Any time in a death case where the client's life could be spared is an extraordinary victory."

Preston Burton, who has been a federal prosecutor and also represented spies such as the FBI's Robert P. Hanssen, said both sides can claim victory. "The government has proven he attempted to spy," Burton said. "But the defense has gotten an acquittal" on the Libya accusation.

Regan, 40, a father of four from Bowie, was arrested at Dulles International Airport in August 2001 as he tried to board a plane to Switzerland.

During the two-week trial in federal court in Alexandria, prosecutors presented evidence showing that Regan was carrying the encrypted coordinates for a Chinese missile site and an Iraqi surface-to-air missile site in his pocket when he was apprehended.

Regan viewed this information at the secret National Reconnaissance Office in Chantilly, where he began working in 1995. At the office, which oversees construction and operation of the nation's reconnaissance satellites, Regan administered the Intelink Web site accessible only by the intelligence community. After retiring from the Air Force, Regan was hired by defense contractor TRW Inc. and resumed work at the office in July 2001.

Prosecutors sketched a portrait of a man saddled with more than $100,000 in debt who offered to betray his country for $13 million. That is the amount Regan sought in a letter prosecutors said he wrote to Hussein offering secret information. FBI agents found that letter, and a similar one to Libyan leader Moammar Gaddafi, when they searched a laptop computer in Regan's home.

But defense attorneys countered that Regan was a decorated government employee with an active fantasy life who may have mishandled classified information but never intended to hurt his country. They said that Regan may have fantasized about being a spy but never became one and that, in any case, the information he was carrying would not have harmed national security.

If the jury decided that Regan is eligible for the death penalty on the Iraq charge, the trial would enter a new death penalty phase before the same panel. Both sides would present arguments again, and jurors would be asked to decide whether Regan should die for the espionage involving Iraq.

If the jury agreed that the Iraq incident was not punishable by death, Regan's conviction on the Iraq espionage would stand and he would face up to life in prison. His sentence would be determined by federal sentencing guidelines that have yet to be calculated.

Brian P. Regan, right, shows little emotion as Judge Gerald Bruce Lee's clerk, Jo Sullivan, reads the partial verdict in federal court in Alexandria.