Law enforcement sources say Lee has not complied with a request that he turn over copies of the nation's most sensitive nuclear weapons codes

October 14, 1999
Web posted at: 10:30 p.m. EDT (0230 GMT)

In this story: 'Crown jewels of nuclear weapon design' Evidence still lacking RELATED STORIES, SITES

From Justice Correspondent Pierre Thomas

WASHINGTON (CNN) -- Investigators looking into the activities of a nuclear scientist linked to allegations of Chinese espionage have been unable to account for copies of top- secret computer files containing secret U.S. nuclear codes, CNN has learned.

Earlier this year, the FBI discovered that Wen Ho Lee, a scientist at the Los Alamos nuclear weapons lab in New Mexico, transferred sensitive nuclear codes, called "legacy codes," from a secure computer to a non-secure computer.

Law enforcement sources say they have determined that at some point, Lee copied the codes on tape. CNN has learned that investigators have asked Lee to produce the tapes, but he has yet to do so.

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Lee, who has been fired from his Los Alamos post, has steadfastly denied wrongdoing and has not been charged with any crime. But the possible loss of key national security secrets could bolster what some have viewed as a shaky case for charging Lee with gross negligence or illegal transfer of classified information.

'Crown jewels of nuclear weapon design'

"It's hard to overstate the importance of the legacy codes. They really are the crown jewels of our nuclear weapon design effort," said Gary Milhollin, a nuclear weapons expert.

"They show you how to design a nuclear weapon, how to manufacture it, how to test it, and they tell somebody who has the codes everything about what our arsenal contains," he says.

Evidence still lacking

Despite the revelations about the missing tape, sources tell CNN that the decision on whether to charge Lee remains a close call because the FBI still does not have evidence that he gave the secrets to anyone.

Last month, after the FBI was unable to prove Lee has passed along designs for the W-88 nuclear warhead, the agency expanded its investigation to include other suspects and government agencies.

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