But the paper stuck to its story, published a month before Mr McVeigh's trial, that he had made a detailed confession. In the Denver, Colorado, court, where he faces the death penalty for the killing of 168 people in the 1995 bombing, lawyers for the Texas paper filed a statement saying it was sensitive to his "fair-trial rights", and would publish nothing more of the leaked material.
Mr McVeigh's attorney, Stephen Jones, denounced the newspaper for printing an irresponsible story based on stolen documents which prejudiced the rights of both his client and the bombing victims. It was one of the "darkest days" for American journalism and the criminal justice system, he said. He accused a reporter of breaking into his computer and rifling electronically through 25,000 pages of documents.
They included FBI interviews and sensitive defence conversations with former CIA officers, foreign governments, and representatives of revolutionary terrorist groups around the world, including the Provisional IRA. Mr Jones said he did not know how how the defence would respond, but legal experts agreed the damage was already done.
Published accounts of conversations between a lawyer and his accused client "undermines the whole purpose of having a trial," said Christopher Mueller, a University of Colorado law professor.
The News, whose circulation area includes Oklahoma City, at the weekend published a story based a memorandum written by an unnamed "defence staffer" from interviews with Mr McVeigh in the six months after the bombing. He insisted he alone drove the rented truck laden with explosives to the front of the building, it reported. He said he bought 5,400lb of ammonium nitrate fertiliser for the home-made bomb and sold stolen firearms to pay for it, a confession which closely matches the government case against him. Perhaps most damning, the "defence staffer" wrote of asking Mr McVeigh, a former soldier with far-right political beliefs, why he did not bomb the government building at night, to lessen casualties.
"Mr McVeigh looked directly into my eyes and told me: 'That would not have gotten the point across to the government. We needed a body count to make our point'." Mr Jones yesterday said the memorandum was not a legitimate defence document and "not a confession".
Clearly trying to shift the focus from his client, he demanded a federal investigation into what he called "theft, fraud and deceit".
Most experts expected the trial to go ahead, even as they agreed Mr McVeigh's chances of a fair trial had been severely compromised. "Move the trial? Where?" asked a former Colorado judge, Jim Carrigan. "Maybe Tahiti. You'd have to find someone living under a rock who doesn't know anything about this case."
Even by the free-for-all standards of US court reporting, the News' story was pushing the limit. It appeared just as potential jurors in Colorado, where the case was moved in an attempt to find a more impartial jury, were returning questionnaires to the judge.
But the publication of privileged lawyer-client conversations, with virtually no chance of their ever reaching the jury, in a capital case, appears unprecedented.
"I don't think we should have a system that allows a newspaper to publish such material," said Professor Mueller. "This is not serving the public interest." It is virtually impossible in the US, barring an immediate risk to national security, to obtain a "prior restraint" injunction to stop a newspaper printing.
In any case, shortly after it contacted Mr Jones for comment, the News published its scoop electronically on its World Wide Web page several hours before it went to press. The move underlined the emerging role of the Internet in the news business, even as it heightened the story's impact. Mr McVeigh has pleaded not guilty, with his alleged co-conspirator, James Nichols, who is to be tried separately. Even in public interviews arranged by his defence, he has not directly denied the bombing. "The only way we can really answer that is by saying we are going to plead not guilty," he said in July 1995 after Newsweek reporters asked: "Did you do it?"