ALSO: New bill would bar lab visits by scientists from 'sensitive' countries

April 28, 1999
Web posted at: 1:06 p.m. EDT (1706 GMT)

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WASHINGTON (CNN) -- A scientist suspected of spying for China may have improperly downloaded huge amounts of secret data from a key U.S. computer system, compromising the nation's nuclear arsenal, sources told CNN.

The sources said the FBI is investigating whether Taiwan-born scientist Wen Ho Lee may have taken information from a secure computer database at the Los Alamos National Laboratory in New Mexico and transferred it to another, less secure system, which could have been accessed from outside of the laboratory.

Lee was the focus of an FBI probe into the alleged theft of nuclear warhead data in the 1980s

Computer data that approximates how U.S. atomic warheads work were downloaded from the Los Alamos computer system, sources told CNN.

But authorities say they have not conclusively determined Lee is responsible for the movement of data.

According to The New York Times, most of the file transfers occurred in 1994 and 1995, just before China signed a nuclear test ban treaty in 1996.

The information -- including codes used to analyze nuclear test results, design nuclear weapons and rate the safety characteristics of nuclear warheads through computer simulation -- is highly classified and would be very useful to U.S. adversaries.

Someone outside of Los Alamos tried to access the material after it was placed in the less secure computer system, CNN's sources said.

Lee, 59, was fired from Los Alamos last month for alleged security violations. He has denied passing classified nuclear weapons information to China and has not been charged with any crime.

China also has denied spying on the United States.

Lee was the focus of an FBI probe into China's alleged theft from Los Alamos in the 1980s of design data for America's most advanced warhead, the W-88.

Los Alamos National Laboratory in New Mexico

Federal investigators did not discover evidence of vast file transfers until recently when they examined Lee's office computer in connection with the probe into the 1980s theft.

The FBI is under increasing scrutiny for how it handled the Lee investigation.

Sources told CNN that Energy Secretary Bill Richardson has ordered an internal review to determine how Lee continued to have access to highly classified material even after he was under investigation.

In a related development, the sources said Lee's wife, Sylvia, who also worked at Los Alamos, had been an FBI informant from 1985 to 1991, providing information on Chinese delegations that toured the nuclear lab.

The FBI disclosed Sylvia Lee's role as an informant to key lawmakers last week, the sources said.

Congressional leaders are angry that they were not told earlier. Lower level FBI officials said they did not believe the information about Mrs. Lee was important and so they did not pass the information on to FBI Director Louis Freeh or to Congress.

Justice Correspondent Pierre Thomas contributed to this report.