N.H. Rev. Stat. Ann. § 7:6

The attorney general shall act as attorney for the state in all criminal and civil cases in the supreme court in which the state is interested, and in the prosecution of persons accused of crimes punishable with death or imprisonment for life. The attorney general shall have and exercise general supervision of the criminal cases pending before the supreme and superior courts of the state, and with the aid of the county attorneys, the attorney general shall enforce the criminal laws of the state. The attorney general shall have the power to collect uncollected debts owed to the state as set forth in RSA 7:15-a.