FBI Whistle Blower Frederic Whitehurst testified yesterday for the defense in the Terry Nichols trial, and he said that another agent, Steven Burmeister, lied:

An F.B.I. whistle-blower testified Wednesday at the state murder trial of Terry L. Nichols that a government scientist lied when he said ammonium nitrate crystals found on debris from the Oklahoma City bombing had been embedded by the force of the blast. The whistle-blower, Frederic Whitehurst, testifying for the defense, said an F.B.I. forensic scientist he had trained, Steven Burmeister, also lied when he testified that the crystals came from the kind of fertilizer believed to have been used in the bombing.

Mr. Whitehurst said there was not enough evidence to support either of Mr. Burmeister's conclusions. "He is my student,'' Mr. Whitehurst said. "And I trust him like a brother. But he lied under oath. He lied."

Q-507. Pieces of crystal embedded in a piece of the truck. That was the exhibit introduced at Timothy McVeigh's trial. It was the only piece of direct evidence that linked the bomb to the Ryder truck:

Mr. Whitehurst's testimony focused on a shredded piece of plywood recovered two days after the bombing that the authorities believe came from the cargo container of the Ryder truck that delivered the bomb. The debris, found in a parking lot across the street from the Alfred P. Murrah Federal Building, is the only direct evidence of the explosive used.

Mr. Whitehurst said that he saw the crystals through a microscope after Mr. Burmeister discovered them but that it was impossible to say whether they were embedded or the result of contamination. Mr. Whitehurst said ammonium nitrate could have been in the parking lot for several reasons.