The judge hearing the case, James Parker, set a hearing for 2 p.m. Monday at U.S. District Court in Albuquerque, when the plea will be entered. If he accepts it, Dr. Lee, 60, could walk from the courtroom a free man after nine months of confinement on the grounds that he had stolen the "crown jewels" of the weapons program with the intent of handing them to a foreign power. Such suggestions have now been abandoned by the government.
The plea agreement was worked out in negotiations after the government suffered a string of courtroom defeats, and after an FBI agent recanted inaccurate testimony about Dr. Lee's behavior. The government faced a deadline this week to hand over thousands of pages of classified documents about why it singled out Dr. Lee in its long investigation.
Dr. Lee is expected to plead guilty to one felony count of the original 59-count indictment, and the other counts, which could have brought him a life sentence, will be dropped.
Important for the government, he has agreed to cooperate with investigators looking into why he improperly downloaded the massive amount of data, 806 megabytes worth, and what he did with it. In particular, he is expected to explain what became of seven computer tapes on which he downloaded data. He will not pay a fine, will not serve more time in prison and will not face probation, say people who have seen the deal.
Mark Holscher, Dr. Lee's principal defense lawyer, said he could not comment on the details of the agreement until Judge Parker signed it. But, Mr. Holscher said, "I can tell you that we are thrilled with the prospect that Dr. Lee may be able to rejoin his family."
The deal offers less than the full exoneration Dr. Lee's family had been seeking. Nevertheless, his daughter, Alberta, and his son, Chung, said in a statement: "We're ecstatic. We are just simply thrilled that he's coming home. We're delighted that this resolution gives him unconditional freedom, and we believe it supports the inescapable conclusion that our father never had any intent to harm a country that he loves."
Patricia Chavez, a spokeswoman for the U.S. attorney's office in Albuquerque, didn't return calls seeking comment.
During negotiations, Dr. Lee's attorneys said that he had destroyed the tapes of the classified information he transferred from top secret government computers, government officials said Sunday. Concern over what Dr. Lee did with the tapes had led some counterintelligence officials to suspect that he might have intended to pass the information to a foreign power, possibly China.
In addition, Dr. Lee agreed to a statement contained in the plea agreement â€“ to be disclosed on Monday â€“ that the government had a legitimate reason to pursue the issue of the missing tapes and investigate what happened to them, an admission that prosecutors hoped would defuse charges that the government had unfairly persecuted Dr. Lee as a Chinese-American scientist.
The information about what Dr. Lee did with the missing tapes was contained in a draft of a document prepared by defense lawyers advising prosecutors of the specific information that Dr. Lee would be prepared to admit if a plea bargain was agreed to, the officials said.
"We got a felony conviction," one government official said. "He's admitted to what he said he didn't do. Finding out what happened to the tapes was a lot more important than putting a 60-year-old man in prison for the rest of his life."
But thus far, Dr. Lee hasn't said why he downloaded large amounts of classified material onto 10 tapes, only three of which have been recovered. Nor has he said what he did with the tapes, who had access to them or whether he had ever given any information about his secret nuclear work to representatives of any government. That information remained to be confirmed in interviews to be scheduled in months to come.
Government officials said they were satisfied by the outcome, clearly hoping to salvage what had become an embarrassing case. They said they had obtained a key concession from Dr. Lee: his commitment to tell investigators why he downloaded classified information and what he did with the tapes.
The deal coalesced Sunday, government officials said, when Attorney General Janet Reno, along with prosecutors in Washington and Albuquerque, accepted the arrangement, after Dr. Lee said he would cooperate fully and tell investigators what he did with the missing tapes.
The sudden and unexpected announcement closes at least a chapter of one of the most publicized, and possibly one of the most important, national security cases of the post-Cold-War era. It hinged not just on questions of who had access to U.S. nuclear weapons secrets and what they did with them, but also on the government's investigative techniques, whether it used racial profiling and perhaps violated the civil rights of a suspect.
From the time Dr. Lee was fired from his job in the top secret X Division of Los Alamos in March 1999, his case has been a rallying point for Asian-American and civil-rights groups. They have said that Dr. Lee was unfairly singled out for a heavy-handed prosecution not because of his actions, which they said were similar to those of many other scientists, but because he was Chinese-American. Dr. Lee, who was born in Taiwan, is a naturalized citizen.