RSA 417:16 Immunity From Prosecution.

If any person shall ask to be excused from attending and testifying or from producing any books, papers, records, correspondence, or other documents at any hearing on the ground that the testimony or evidence required of such person may tend to be self-incriminating or subject such person to a penalty or forfeiture, and shall notwithstanding be directed to give such testimony or produce such evidence, the person must nonetheless comply with such direction, but shall not thereafter be prosecuted or subjected to any penalty or forfeiture for or on account of any transaction, matter or thing concerning which such person may testify or produce evidence pursuant thereto, and no testimony so given or evidence produced shall be received against the person upon any criminal action, investigation