RSA 666:12: Testimonial Privilege.

No witness in any proceeding for the violation of election laws shall be excused from giving his testimony upon the ground that such testimony would incriminate him; but no such testimony shall be used against him at any time or in any prosecution. Any person who voluntarily discloses the facts to the proper authorities and procures a conviction in any such proceeding shall not be prosecuted for his connection with the bribery or attempted bribery.