In an interview for the CBS documentary programme, 60 Minutes, Wen Ho Lee said in his first public statement since the spy scandal broke this spring, that he had done nothing to jeopardise US security and had "spent the best years of my life trying to make [the United States] stronger".
Mr Lee agreed that he had transferred top secret files from his high- security computer to a less secure one, but said many scientists did the same and the second computer was adequately protected, claims supported by other former laboratory workers.
Mr Lee was dismissed from his job as a weapons designer at the Los Alamos laboratory after 21 years' service following a New York Times expose naming him as chief suspect in the alleged transfer of secret warhead blueprints to China.
But despite a hue and cry about the most damaging spy scandal since the Cold War, the charges have not been substantiated, and the Federal Bureau of Investigation has insufficient evidence to prosecute.
On the 60 Minutes programme, the Energy Secretary, Bill Richardson, said there was compelling evidence that Mr Lee had violated laboratory security procedures and noted he had failed two lie-detector tests. He did not deny reports that Mr Lee's wife, Sylvia - also a Los Alamos employee - was a paid FBI informer.
Chinese officials deny that secrets were stolen, saying everything they obtained was available from published sources and the Internet.Reuse content