In a new memoir, former Los Alamos scientist Wen Ho Lee says the nuclear "crown jewels" he was accused of mishandling were really the "crown junk" and were not vital to national security.

The files he downloaded were old, with much of the information already public and very little of it classified, Lee says in My Country Versus Me, published by Hyperion. He says he copied the material onto tapes because he had lost files before and did not trust the computer system.

He describes himself as a loyal "Cold Warrior" for the United States, yet says the FBI threatened him with execution "like the Rosenbergs" if he did not confess to giving nuclear secrets to China.

"I want to share through this book how I fell into a trap," Lee says, "one slippery step at a time, not even realizing what was happening until it was too late."

Lee, a Taiwanese-born naturalized citizen, was arrested in December 1999 and indicted on 59 felony counts alleging he transferred nuclear weapons information to portable computer tapes. He was held in solitary confinement for nine months, though never charged with spying.

As the government's case crumbled, Lee pleaded guilty to a felony count of downloading sensitive material, and was set free. The FBI's mishandling of the case was a major embarrassment for the bureau.

While Lee was behind bars, one senior scientist called the files "the crown jewels."

Lee says the downloaded tapes were all work-related, routine and contained in a secure area at Los Alamos National Laboratory

"In fact, the 'crown jewels' are largely the crown junk," he says. "This is the biggest nuclear weapons secret that LANL and the government have to hide."

Lee says he copied the files — needed to design computer simulations for nuclear explosions — so he could have backup copies.

"In 1993, I lost several files as a result of a computer system conversion at the lab," he says. "One of the codes I lost was about nuclear reactor safety. ... This was an important code, and it was gone."

A call to the U.S. attorney's office in Albuquerque on Friday was not immediately returned.

Lee, who has been a U.S. citizen since 1974 and spent 20 years doing top-secret work at the lab, is suing the government for defamation and claims he was targeted because he is ethnic Chinese.

"Had I not been Chinese," he says, "I never would have been accused of espionage and threatened with execution. ... Now I know that political whimsy can destroy the contributions of a life's work."

In a recent deposition made public Friday, former Energy Secretary Bill Richardson said that ethnicity was not a factor in his firing of Lee or the decision to investigate him for possible security breaches.

While in solitary at the Santa Fe County Jail, Lee says, he was kept shackled and handcuffed during exercise periods with a soccer ball. The 62-year-old colon cancer survivor says he had difficulty getting the special diet he needed and lost weight.

"How will I ever forget this nightmare?" he asks.

Lee said he was threatened with execution in March 1999, when he was interrogated by FBI agents: "They told me that unless I confessed to giving nuclear secrets to China, I might be executed, like the Rosenbergs." Julius and Ethel Rosenberg went to the electric chair in 1953 for giving atomic secrets to the Soviets.

The accusation of espionage, leaked to news media, was never formally lodged against Lee. Prosecutors conceded the evidence was insufficient.

Lee speculates that at least some of his troubles might have been averted if he had not thrown away his data tapes.

Demoted from the lab's top-secret X Division after the espionage leaks, Lee says he was confronted with the problem of what to do with the classified data he was no longer entitled to possess. He deleted files with help from the lab help desk, he says, and threw the computer tapes into a lab trash bin.

The unaccounted-for tapes triggered near-frenzy at the FBI, which insisted on proof they had not been turned over to a foreign government. Except for giving his word, Lee could not provide that proof. Agents searched for days at the Los Alamos County landfill for the tapes.

Lee says even today, his wife, Sylvia, "still has nightmares about being awakened by the FBI." The Lees plan to stay in Los Alamos. Lee says he has his garden, favorite fishing spots and a safe, secure environment.

"The main reason for us to stay here is the warmth of our neighbors, our friends and the real community we are part of," he says.