Los Alamos National Laboratory has fired two internal investigators after someone delivered their reports alleging widespread theft and fraud at the lab to a national watchdog group.

At least one congressional investigation was already under way Tuesday, a day after Glenn Walp and Steven Doran received identical letters terminating their employment.

Walp and Doran were hired this year to investigate the nuclear research lab's handling of government property and money. They said they uncovered a lack of controls on money and high-tech hardware.

Walp submitted a report to Los Alamos authorities in March that listed 263 desktop or laptop computers as missing since 1999, many of them presumed stolen. In all, about $2.7 million worth of equipment is unaccounted for, according to Walp's reports.

"I think there has been a culture that has been embedded in that environment that is almost conducive to committing a theft," he said Tuesday by phone from Santa Fe.

Reporting a desktop computer lost, he wrote, "is parallel to my spouse telling me she just lost the refrigerator."

Information on the pair's findings was turned over anonymously to news media and to the Project on Government Oversight, a Washington, D.C.-based nonprofit watchdog group. Walp and Doran said they were not the source.

Lab spokesman Jim Danneskiold said he couldn't say why Walp and Doran were fired. But he said the lab did not need a reason because both were still in their probationary phase of employment and subject to discretionary dismissal -- as long as the firings were not retaliatory.

"The laboratory's position is that there was no retaliation in these two terminations," Danneskiold said.

Both Walp and Doran said Tuesday that they had done nothing wrong and would work with Congress and the FBI to clear up the climate at the lab. Doran blamed lab officials for "roadblocking" the investigation with legal maneuvers and said he and Walp had aggressively pushed higher-ups at the lab to do something about the lack of controls on money and high-tech hardware.

"I think there has been a culture that has been embedded in that environment that is almost conducive to committing a theft," Walp said Tuesday.

Danneskiold responded: "I have worked for the lab for 12 years and haven't observed that culture."

Danneskiold said that the lab, as any institution would, consulted legal counsel when allegations of wrongdoing were uncovered.

"The FBI is forwarded any evidence as soon as it comes to the lab's attention," he said, noting that Los Alamos officials have cooperated since the investigation began.

The University of California operates the nuclear weapons laboratory for the Department of Energy.

Rep. Jim Greenwood, chairman of the House Energy and Commerce Committee's investigative arm, said in a telephone interview Tuesday that the subcommittee would probably look into the firings.

In a letter to the University of California earlier this month, the Pennsylvania Republican asked for documents relating to the lab's guidelines for purchasing equipment.

Security at the lab has been under scrutiny since scientist Wen Ho Lee was fired and accused of dozens of lab security violations. Lee pleaded guilty in September 2000 to a single count of using an unsecured computer to download a defense document and a federal judge freed him with an apology.