Federal agents found much of the information produced by the Bush administration’s top-secret warrantless surveillance program vague and difficult to use, a sweeping review of the program found. Then-President George Bush and other top administration officials have said the program was a critical tool in preventing terrorist attacks. However, a report Friday by the inspectors general of the CIA, the Justice Department, the Pentagon and other agencies found that some FBI and CIA agents were frustrated by the secrecy surrounding the program
