Two companies that will share in a new FBI computer contract were singled out in a government audit Monday that questioned $17 million in the agency's computer overhaul.

The FBI and its contractors share the blame for $10 million in questionable costs and for 1,205 pieces of missing computer equipment valued at $7.6 million, the Government Accountability Office said in its review of the FBI's Trilogy program.

Two of those companies, CACI and Computer Sciences Corp., are part of the Lockheed Martin Corp. team that last week won a six-year, $305 million contract to build and run the FBI's Sentinel computerized case management system. The total value of the Sentinel project is $425 million.

FBI officials said they were applying the lessons learned in the Trilogy computer upgrade, including keeping tighter reins on their contractors. Sentinel is the replacement for the failed project that was to have been the final piece of Trilogy.

The questionable costs included first-class air travel for government contractors, excessive overtime and $5.5 million in charges that lacked substantiation, the report by Congress' investigative and audit agency said.

The FBI was "highly vulnerable to payments of unallowable costs" because of lax oversight, auditors said.

El Segundo, Calif.,-based Computer Sciences, or CSC, was the principal contractor in the effort to put in place a high-speed, secure computer network and 30,000 new desktop computers for the FBI. CACI of Arlington, Va., essentially reported to CSC.

Auditors identified a $456,211 invoice from CACI for which CSC never received sufficient evidence, but paid anyway. "It's not what we asked for but at this point it doesn't really matter. Approve it," one CSC employee wrote another in an e-mail exchange that was included in the GAO report.

In another bill from CSC to the FBI, all but $44,000 of a $1.95 million invoice was listed as "other direct costs" with no additional explanation provided.

Auditors also identified as excessive the $52,000 CACI spent on 60,000 pens that were custom-made for FBI computer training sessions.

Representatives of the companies did not immediately comment Monday.

A separate report last week from Justice Department inspector general Glenn A. Fine warned that costs could again get out of hand unless the FBI puts strong controls in place. Bureau officials have said they are doing just that.

"The lessons learned from the Trilogy program are guiding us, and the FBI continues to strengthen our internal controls," said FBI spokeswoman Cathy Milhoan.

The CSC unit that worked on Trilogy will not be part of the Sentinel project, Milhoan said. CACI will provide training for new system, as it did for Trilogy, she said.

The FBI has since accounted for more than 1,000 of the missing desktop and laptop computers, printers and servers, she said. The bureau also will seek repayment of inappropriate charges identified by a final audit of Trilogy that has yet to be finished, Milhoan said.