N.H. Rev. Stat. § 21-M:3-b

The attorney general, as the chief law enforcement officer for the state, shall have authority to vest with statewide law enforcement authority any municipal or state law enforcement officer assigned by the employing authority to work under the guidance and direction of the attorney general for the purpose of conducting or assisting with criminal law investigations being conducted by the attorney general's office, including, but not limited to, service on the attorney general's drug task force. The grant of authority shall be valid only for the duration of the officer's assignment to the department of justice. Any law enforcement officer vested with statewide law enforcement authority pursuant to this section shall be a state official for the purposes of being entitled to defense and indemnification under RSA 99-D:2, in accordance with the terms of any written agreement between the attorney general and the employing authority and subject to any limitations set forth in such written agreement.