(1) Nothing in section 86 shall be deemed to effect the operation of sections 123 and 124 of the Indian Evidence Act, 1872 (1 of 1872) or to apply to any letter, postcard, telegram or other document in the custody of the postal or telegraph authorities.
     (2) If any document in such custody is, in the opinion of any District Magistrate, Chief Judicial Magistrate, Court of Session on High Court wanted for the purpose of any Security Guard Court, such Magistrate or Court may require the postal or telegraph authorities, as the case may be, to deliver such document to such person as such Magistrate or Court may direct.
     (3) If any such document is, in the opinion of any other Magistrate or of any Commissioner of Police or District Superintendent of Police, wanted for any such purpose, he may require the postal or telegraph authorities, as the case may be, to cause such search to be made for, and to detain such document pending the order of any such District Magistrate, Chief Judicial Magistrate, Court of Session or High Court.