N.H. Rev. Stat. Ann. § 358-A: § 358-A:8

I.
Authority of Attorney General. The attorney general shall have the power to subpoena and subpoena duces tecum in the name of the attorney general for the purposes of this chapter. Witnesses summoned by the attorney general shall be paid the same fee and mileage that are paid witnesses in the superior court of the state. A subpoena or subpoena duces tecum of the attorney general may be served by any person designated in the subpoena or subpoena duces tecum to serve it. The attorney general may administer an oath or affirmation to any person and conduct hearings in aid of any investigation. The attorney general may also require any person to make a statement in writing under oath concerning any matter under investigation provided that the due date for receipt of such a statement shall be no sooner than 10 calendar days after receipt of such demand. Any testimony or statement given by any person so sworn shall be subject to the pains and penalties of perjury.
II. Without limiting the authority granted in paragraph I, whenever the attorney general believes any person to be or to have been in violation of this chapter, the attorney general may examine or cause to be examined for that purpose any books, records, papers, or other documentary materials, or may examine any person under oath and subject to the pains and penalties of perjury that the attorney general thinks may have knowledge of such violation. For such examination, the attorney general may require the person to appear at such person's place of residence, place of business or any place in this state.
III.
Notice.
(a) The attorney general shall serve notice of the time, place, and cause of said examination at least 10 days prior to the date of the examination. Service of any such notice may be made by:
(1) Delivering a duly executed copy of the notice to the person to be served or an agent authorized by law to receive service of process; or
(2) Delivering a duly executed copy of the notice to the person's principal place of business in this state, if any; or
(3) Registered mail, return receipt requested, to the person to be served, or an agent authorized by law to receive service of process. These limitations do not apply to a written statement required under paragraph I which can be required by a reasonable notice thereof.
(b) Such notice need not be given if the attorney general has reason to believe that any potential recipient of such notice may move, conceal, alter or destroy, or cause to be moved, concealed, altered or destroyed, any documents to which it refers, or move or conceal or cause to be moved or concealed any person whose testimony is sought pursuant thereto. In any of such cases, the notice served by the attorney general pursuant to this paragraph may require the immediate production or examination of any document or person therein referred to.
IV.
Limitations. No such notice shall make improper or unreasonable requirements, nor require the production of privileged information.
V.
Extension; Modification. At any time prior to the date specified in the notice, or within 21 days after the notice has been served, whichever period is shorter, the superior court may, upon motion for good cause shown, extend said reporting date, or modify or set aside the demand. The motion may be filed in the superior court of the county in which the person resides or in which the person's usual place of business is located, or in Merrimack county.
VI.
Use of Information. Any information, testimony, or documentary material obtained under the authority of this section shall be used only for one or more of the following purposes:
(a) In connection with investigations instituted under this chapter or for the prosecution of legal proceedings instituted under this chapter or other provisions of the RSA; and
(b) In connection with any formal or informal program of or request for information exchange between the department of justice and any other local, state or federal law enforcement agency. However, no information or material obtained or used pursuant to the authority of this section shall be released publicly by any governmental agency except in connection with the prosecution of legal proceedings instituted under this chapter or other provisions of the RSA. In addition, any information, testimony or documentary material obtained or used pursuant to a protective order shall not be exchanged or released, as provided herein, publicly except in compliance with such protective order.
VII.
Penalty. Any person who fails to comply with any notice served upon such person under this section shall be fined not more than $5,000.