In an expansion of an espionage investigation disclosed last year, a Defense Department official has been charged with conspiring to provide classified information to an agent with ties to the People's Republic of China (PRC).

The accused, James Wilbur Fondren Jr., 62, was a civilian employee at the Pentagon and the deputy director of the Washington Liaison Office of the U.S. Pacific Command. He retired from active duty in the U.S. Air Force as a lieutenant colonel in 1996. He has been on administrative leave since February 2008, when the Justice Department announced the arrests of several individuals for stealing military aerospace secrets and sending them to China.

One of the individuals arrested last year was Tai Shen Kuo, a furniture businessman and a naturalized U.S. citizen. Another was former Defense Department employee Gregg William Bergersen.

In March 2008, Bergersen pleaded guilty to conspiring to provide U.S. defense information to China and was later sentenced to almost five years in prison.

In May 2008, Kuo pleaded guilty to similar charges. He subsequently was sentenced to more than 15 years in prison. Kuo was a close associate of Fondren's and was a guest at Fondren's house at the time of his arrest. Fondren allegedly believed Kuo to have ties with officials in Taiwan rather than with the PRC.

The FBI affidavit in Kuo's case describes a sweeping surveillance operation directed at Kuo. In addition to physical surveillance, the FBI monitored his e-mail accounts at Bellsouth.net, Gmail, and Hotmail, as well as his telephone communications. The agency also covertly copied the hard drive on Kuo's laptop and placed audiovisual surveillance equipment in a car Kuo rented.

The FBI affidavit filed as part of the case against Fondren suggests that the agency's eavesdropping operation helped incriminate Fondren as well as Kuo. It includes transcripts of several conversations between Fondren and Kuo about the transfer of classified information that allegedly occurred in Fondren's Annandale, Va., home.

Dana J. Boente, acting U.S. attorney for the Eastern District of Virginia, called the allegations in the Fondren case "troubling" and said, "The U.S. government places considerable trust in those given access to classified information, and we are committed to prosecuting those who abuse that trust."

Rick Howard, director of security intelligence at VeriSign iDefense, said that this kind of espionage goes on all the time. "All governments have espionage operations where they're trying to turn people to give them inside information," he said.

It's noteworthy, he said, that this isn't cyberespionage. "It's traditional spy-vs.-spy stuff," he said.

Howard said that while every organization that deals with sensitive information has procedures to protect that information, "it's not too hard to defeat those things if you're determined."