N.H. Rev. Stat. Ann. § 21-V:9

No person employed or contracted by or volunteering for the office shall be compelled to testify or produce evidence in any judicial or administrative proceeding with respect to any matter involving exercise of his or her official duties except as may be necessary to enforce this chapter. All related memoranda, work product, notes, or case files of the office are confidential and are not subject to discovery, subpoena, or other means of legal compulsion, and are not admissible in evidence in a judicial or administrative proceeding. This limitation shall not apply to information obtained by any employee, contractor, or volunteer of the office regarding a crime or fraud, or a communication of imminent risk of serious harm, nor shall it apply to communications regarding the general operation of the office and the processes employed.