WASHINGTON — Timothy McVeigh says he did it, and he is not sorry.

"I understand what they felt in Oklahoma City. I have no sympathy for them," the convicted killer of 168 people said, after detailing how he planned and carried out the 1995 bombing of the Murrah federal office building.

As a legal matter, McVeigh's confession is worthless. He admitted the bombing to book authors, not in court.

That he said it, however, makes it difficult for many to understand the furor over an FBI mistake that has postponed McVeigh's scheduled execution and could ultimately reopen the legal question of his guilt.

"I understand why lay people, and especially the victims, would say, 'hey, he confessed, he admitted it, so what's the big deal?' " said G. Allen Dale, a Washington criminal defense lawyer.

But people do confess, sometimes repeatedly, to crimes they did not commit, and it is the government's responsibility to prove guilt in court, Dale and other lawyers said.

"The government has got the burden of proof. They can't withhold documents and evidence and then expect to kill someone," Dale said.

The Justice Department admitted Thursday that more than 3,000 documents gathered by the FBI before McVeigh's trial were never given to his defense team, as required by law.

On Friday, Attorney General John Ashcroft postponed McVeigh's execution, scheduled for Wednesday. McVeigh and his lawyers are mulling their options.

McVeigh could ask for another delay in the execution, now set for June 11, or make a broad new assault on his conviction.

His published statements confessing to the bombing could then be brought into court but would still not equal a straightforward confession to a law enforcement officer.

"I believe what most people feel now is that he's confessed outside of the courtroom. It just reinforces what was proved and found by the jury during the trial," Beth Wilkinson, a former prosecutor in the case, said Sunday on CBS' "Face the Nation."

One of McVeigh's current lawyers, Robert Nigh, said on NBC's "Meet the Press" that "there has been no evidence at the time of trial concerning any statement by Mr. McVeigh, and you have to analyze the case in terms of the evidence at the time of trial."

The twist derailed what had seemed an orderly progression toward the first federal execution since 1963, although Ashcroft said he is confident the documents will not put McVeigh's guilt in doubt.

"This feels incongruous to people, it feels unimaginable to people, but we have had examples," of false or coerced confessions, said Elizabeth Semel, director of the American Bar Association's Death Penalty Representation Project.

McVeigh pleaded innocent and did not cooperate with prosecutors or the FBI. He was convicted in 1997 and sentenced to death. Last year, McVeigh asked his lawyers to stop fighting the case.

McVeigh seemed ready to die. But until March and publication of "American Terrorist: Timothy McVeigh and the Oklahoma City Bombing," McVeigh had never publicly admitted guilt.

McVeigh told the authors he knew he would get caught and even anticipated execution as a form of "state-assisted suicide."

His apparent desire for martyrdom is one reason the FBI documents are so troubling and a reason to take his confession with a grain of salt, said Lawrence Goldman, vice president of the National Association of Criminal Defense Lawyers.

"We don't just say someone is guilty because he says he is," Goldman said. "There are always people who have political motives, maybe who have humdrum lives, who want to go down in history as a martyr."

The federal government McVeigh professed to despise should not play into his hands by giving him anything less than scrupulously fair treatment now, Goldman and other lawyers said.

McVeigh might never have admitted guilt at all had the witness statements and other documents from the FBI investigation been turned over on time, said Peter Greenspun, a Virginia criminal defense lawyer.

McVeigh only spoke when his trial was over, his appeals complete and his death sentence seemingly assured.

"If all those pages contained something significant from a defense perspective, it might have clouded the chance for a conviction, or it may have provided more of a basis for an appeal," Greenspun said. "The combination of these things may have dissuaded McVeigh from making the statements."