A new case management system being implemented by the U.S. Federal Bureau of Investigation to help fight terrorism could cost as much as $500 million, blowing away the $170 million it sank into a previous project that was abandoned a year ago, according to a government watchdog group.

In a 91-page audit report released Tuesday by the inspector general's office in the U.S. Department of Justice ( .pdf available), cost estimates for the new FBI IT system range from $400 million to $500 million, based on information provided by the FBI to congressional inquiries. An exact figure for the project is expected when the FBI finalizes a contract for the system, called Sentinel. That contract award is officially expected sometime in the next 30 days, but Tuesday an FBI spokeswoman said that it will come shortly.