"VA's Inspector General, the FBI and local law enforcement are conducting a thorough investigation of this matter," said Secretary of Veterans Affairs R. James Nicholson said in a statement. Unisys told the VA on Aug. 3 that the computer was missing from its Reston, Va., offices. The VA immediately sent a team to Unisys to help search for the missing computer and to determine exactly what information it contained.

The VA said it believes the data involved is limited to veterans who received treatment at the two Pennsylvania medical centers during the past four years. According to the agency, the desktop computer may have contained patients' names, addresses, Social Security numbers, dates of birth, insurance carriers and billing information, dates of military service, aswell as claims data that may include some medical information.

The VA estimates that the computer contained information on approximately 5,000 patients treated at the center in Philadelphia, approximately 11,000 patients treated at the Pittsburgh facility, and about 2,000 deceased patients. The VA is also investigating the possibility that the computer contained information on another 20,000 people who received care through the Pittsburgh medical center.

VA officials are also working with Unisys regarding an offer of credit monitoring and individual notifications to those who may be affected. Unisys officials could not be reached for comment last night.

As soon as VA personnel learned the computer was missing, they immediately notified the appropriate senior VA leaders, including the Nicholson and the deputy secretary; appropriate congressional offices and committees; the VA's Office of the Inspector General; and other law enforcement authorities, including the FBI and the Department of Homeland Security's Computer Emergency Response Team.