Where any document--
(i) is produced or furnished by any person or has been seized from the custody or control of any person, in either case, under this Act or under any other law; or
(ii) has been received from any place outside India (duly authenticated by such authority or person and in such manner as may be prescribed) in the course of investigation of any contravention under this Act alleged to have been committed by any person,
and such document is tendered in any proceeding under this Act in evidence against him, or against him and any other person who is proceeded against jointly with him, the court or the Adjudicating Authority, as the case may be, shall--
(a) presume, unless the contrary is proved, that the signature and every other part of such document which purports to be in the handwriting of any particular person or which the court may reasonably assume to have been signed by, or to be in the handwriting of, any particular person, is in that person's handwriting, and in the case or a document executed or attested, that it was executed or attested by the person by whom it purports to have been so executed or attested;
(b) admit the document in evidence notwithstanding that it is not duly stamped, if such document is otherwise admissible in evidence;
(c) in a case falling under clause (i), also presume, unless the contrary is proved, the truth of the contents of such document.