Section 17B. Whenever the attorney general or a district attorney has reasonable grounds for belief that the service of a common carrier, subject to the jurisdiction of the department of telecommunications and energy, as defined in paragraph (d) of section twelve of chapter one hundred and fifty-nine, furnished to a person or to a location, is being or may be used for an unlawful purpose he may, acting within his jurisdiction, demand all the records in the possession of such common carrier relating to any such service. Such common carrier shall forthwith deliver to the attorney general or district attorney all the records so demanded. No such common carrier or employee shall be civilly or criminally responsible for furnishing any records or information in compliance with said demand.