I disagree. He could have taken copies of the files as insurance before whistleblowing, allowing him to then go public if nothing resulted from the official inquiry.

You believe that the Government could hide/destroy all archival Target Development packages, SIGINT Reporting, Full Motion Video, Tactical Reports, Collateral Damage Estimates, Judge Advocate and other leadership decisional communications, Battle Damage Assessments, Political Communications, and other material about any particular strike in question to prevent the investigation of a whistleblowers claims?