Updated

Authorities in northern New Mexico have stumbled onto what appears to be classified information from the Los Alamos nuclear weapons laboratory while arresting a man suspected of domestic violence and dealing methamphetamine from his mobile home.

Sgt. Chuck Ney of the Los Alamos Police Department said the information was discovered during a search last Friday of the man's records for evidence of his drug business.

Police alerted the FBI to the secret documents, which agents traced back to a woman linked to the drug dealer, officials said. The woman is a contract employee at Los Alamos National Laboratory, according to an FBI official who spoke on condition of anonymity because of the sensitive nature of the case.

The official would not describe the documents except to say that they appeared to contain classified material and were stored on a computer file.

FBI special agent Bill Elwell in Albuquerque confirmed that a search warrant was executed on Friday night, but he refused to discuss details.

"We do have an investigation with regard to the matter, but our standard is we do not discuss pending investigations," Elwell said.

A lab spokesman declined to comment.

Los Alamos has a history of high-profile security problems in the past decade, with the most notable the case of nuclear scientist Wen Ho Lee, who was charged with 59 counts of mishandling sensitive information. After he pleaded guilty in 2000 to mishandling computer files, the other charges were dismissed, he was freed after nine months in solitary confinement, and a federal judge apologized for the government's treatment of him.

In 2004, the lab was essentially shut down after an inventory showed that two computer disks containing nuclear secrets were missing. A year later the lab concluded that it was just a mistake and the disks never existed.

But the incident highlighted sloppy inventory control and security failures at the nuclear weapons lab. And the Energy Department began moving toward a five-year program to create a so-called diskless environment at Los Alamos to prevent any classified material being carried outside the lab.

Even though Los Alamos is now under new management, Danielle Brian, executive director of the watchdog group Project on Government Oversight said the lab has not done much to clean up its act.

"Los Alamos has always seemed to be rewarded for its screw-ups," Brian said. "We're waiting with baited breath to see if anything has changed."

The idea that police found classified documents at a home where a drug sting was being conducted is disturbing, she said.

"The problem is when you actually have those materials that are supposed to be protected inside the lab and you find them outside the lab in the hands of criminals — that should worry everybody," Brian said.

The FBI and the U.S. attorney's office in Albuquerque were "evaluating the information obtained as a result of the search warrant," Elwell said.

The federal charge of unauthorized removal and retention of classified material is a misdemeanor that carries a maximum sentence of a year in prison and up to a $100,000 fine.