shall determine the matter de novo, and may examine the contents of such agency records in camera to determine whether such records or any part thereof shall be withheld under any of the exceptions provided under subsection (b)(4), and the burden is on the agency to sustain its action. (B) Notwithstanding any other provision of law, the defendant shall serve an answer or otherwise plead to any complaint made under this subsection within 30 days after service upon the defendant of the pleading in which such complaint is made, unless the court otherwise directs for good cause shown. (3) Attorney fees The court may assess against the United States reasonable attorney fees and other litigation costs reasonably incurred in any case under this subsection in which the complainant has substantially prevailed. (4) Special Counsel Whenever the court orders the production of any agency records improperly withheld from the complainant and assesses against the United States reasonable attorney fees, litigation costs, and interest, and the court additionally issues a written finding that the circumstances surrounding the withholding raise questions whether agency personnel acted arbitrarily or capriciously with respect to the withholding, a Special Counsel shall promptly initiate a proceeding to determine whether disciplinary action is warranted against the officer or employee who was primarily responsible for the withholding. A Special Counsel, after investigation and consideration of the evidence submitted, shall submit his findings and recommendations to the administrative authority of the agency concerned and shall send copies of the findings and recommendations to the officer or employee or his representative. The administrative authority shall take the corrective action that the Special Counsel recommends. (5) Contempt In the event of noncompliance with the order of the court, the district court may punish for contempt the responsible employee, and in the case of a uniformed service, the responsible member. 8.