N.H. Rev. Stat. Ann. § 82-A:11-a

For the purpose of administering and enforcing the provisions of this chapter and in order to assist the bureau of emergency communications, division of emergency services and communications, of the department of safety, in its administration of RSA 106-H:9, the department or any officer or employee of the department designated by the commissioner, may undertake investigations concerning matters covered by this chapter and RSA 106-H:9 and may examine any books, papers, records, or memoranda bearing upon the business transacted or purchased by any such retailer or taxpayer.