Although the audit by the inspector general concluded that the FBI was doing a better job of hanging on to its laptops than it had in the past -- during an earlier review period losses averaged more than 11 a month -- it criticized the agency for not enforcing its own rules on reporting lost or stolen hardware. And the inspector general hit the agency for not being able to detail the contents of the laptops.

Ten of the computers had confidential or sensitive data on their hard drives, according to the report, including one stolen in the Boston area that included software for creating FBI identification badges. And 51 other systems also may have contained secrets. Of those, six had been assigned to the FBI's counterintelligence division and one had been with the agency's counterterrorism division.

"The FBI did not know the content of these computers or whether they contained sensitive or classified information," said the report. "Without knowing the contents of these lost and stolen laptop computers, it is impossible for the FBI to know the extent of the damage these losses might have had on its operations or on national security."

Counterintelligence and Counterterrorism are two departments in the FBI regularly entrusted with the agency's most confidential information.

The same audit also uncovered the loss of 160 FBI weapons, including 10 shotguns, six submachine guns and eight rifles, during the 44-month span. Unlike the majority of the laptops, which were reported as lost, 59 percent of the weapons were stolen, many from agents' vehicles.