law: 22. Power of authority to impound documents.-
  (1) Where any books of account or other documents are produced before the authority in any proceedings under this Act and the authority in this behalf has reason to believe that any of the books of account or other documents are required to be impounded and retained for any inquiry under this Act, it may impound and retain the books of account or other documents for a period not exceeding three months from the date of order of attachment made by the Adjudicating Authority under sub-section (3) of section 26:
  Provided that the period for retention of the books of account or other documents may be extended beyond a period exceeding three months from the date of order of attachment made by the Adjudicating Authority under sub-section (3) of section 26 where the authority records in writing the reasons for extending the same.
  (2) Where the authority impounding and retaining the books of account or other documents, under sub-section (1) is the Initiating Officer, he shall obtain approval of the Approving Authority within a period of fifteen days from the date of initial impounding and seek further approval of the Approving Authority for extending the period of initial retention, before the expiry of the period of initial retention, if so required.
  (3) The period of retention of the books of account or other documents under sub-section (1) shall in no case exceed a period of thirty days from the date of conclusion of all the proceedings under this Act.
  (4) The person, from whom the books of account or other documents were impounded under subsection (1), shall be entitled to obtain copies thereof.
  (5) On the expiry of the period specified under sub-section (1), the books of account or other documents shall be returned to the person from whom such books of account or other documents were impounded unless the Approving Authority or the Adjudicating Authority permits their release to any other person.