Updated

The Justice Department released on Wednesday a massive review of the FBI's bungled espionage investigation of former nuclear scientist Wen Ho Lee.

The report, most of which was leaked earlier, criticizes the FBI for never considering the Lee investigation a priority; failing to allot it proper resources or properly supervise agents on the case; and moving too slowly.

It condemns the communication breakdown between the FBI and the Energy Department and chastises investigators for not immediately searching Lee's computer files when suspicions first arose. That left critical weapons secrets unprotected, the report said.

"The Wen Ho Lee investigation involved allegations of espionage as significant as any the United States government is likely to face," wrote Randy Bellows, a federal prosecutor who led the team that reviewed the investigation of the former scientist at the Los Alamos National Laboratory in New Mexico.

"It required an appropriate, aggressive and effective response. It did not get such a response from any of the departments and agencies whose conduct we have examined, and the gravity of this failure may yet not be fully known," he said.

The FBI said it had made changes as a result of the inquiry. "This inquiry has led to a fundamentally different approach to counterintelligence," bureau spokesman Jay Spadafore said Wednesday.

He said the report "contained over 40 recommendations, and the FBI has worked through all of them. In some cases, we have gone further than what was recommended."

Lee was held in solitary confinement for nine months and indicted on 59 felony counts alleging he transferred nuclear weapons information to portable computer tapes. He was never charged with spying and denied giving information to China.

As the government's case crumbled, Lee pleaded guilty to a felony count of downloading sensitive material.

In May 1999, then-Attorney General Janet Reno assigned Bellows and a team of investigators to report on the investigation. The report was completed a year later but had not been released until Wednesday because of secrets it held.

The report is littered with black smears where attorneys for the Energy Department, FBI and CIA have deleted portions for secrecy or privacy. One full chapter was blacked out.

"The report stands as a harsh critique of the government's investigation of espionage at Los Alamos, but this is a mystery that remains unsolved," said Steven Aftergood, a government secrecy expert for the Federation of American Scientists. He said, for instance, there remains no explanation how China got specifications for U.S. weapons.

The terrorist attacks of Sept. 11 have influenced the FBI's mission and structure, including surveillance rules for suspected spies.

"It's too early to say the chapter is closed, but this is a substantial contribution to our understanding of this puzzling event," Aftergood said.

Lee has sued the government for defamation. Additionally, the Energy Department's former intelligence chief has sued Lee for defamation, after supporters of Lee claimed the investigation focused on the scientist because he was born on Taiwan.