And before the trial, Mr. Ellison told the prosecutor that at Mr. Snell's request he had entered the Federal Building in Oklahoma City to gauge what it would take to damage or destroy it.

Afterward, he testified in court, he made preliminary sketches and drawings. Rocket launchers were to be "placed in a trailer or a van so that it could be driven up to a given spot, parked there, and a timed detonating device could be triggered so that the driver could walk away and leave the vehicle set in position, and he would have time to clear the area before any of the rockets launched."

"And I was asked to make it so it would fit in either a trailer or a van or a panel truck," Mr. Ellison continued.

"Ellison," Mr. Snyder recalled, "said that Snell was bitter toward the Government because of the I.R.S. And I think these were agents from the Oklahoma City office, and they had taken him to court, and his property had been seized by the F.B.I. and other agents in a raid. But you can't be sure about any of this, because a Federal raid, to a lot of these people, is any time the postman brings the mail."

In 1984, a black state trooper stopped Mr. Snell for a traffic violation near De Queen, Ark. Mr. Snell shot the trooper, Louis Bryant, as he approached the vehicle, then shot him again as he lay on the ground, killing him. Mr. Snell always contended afterward that he had killed the officer in self-defense.

Mr. Snell fled and was chased to Broken Bow, Okla., where he was wounded in a gun battle with the authorities before he was subdued. In his car, the police found a gun that had been used the previous year in the robbery and murder of William Stumpp, a Texarkana pawnbroker. Mr. Snell was convicted of both murders and sentenced to death in the Stumpp case.

Mr. Snell always denied that murder, but Mr. Ellison said at the sedition trial that Mr. Snell had killed Mr. Stumpp because he believed -- wrongly, as it turned out -- that Mr. Stumpp was Jewish.