Mass. Gen. Laws ch. 62C, § 20: Inspection of returns, books, accounts and other records in possession of commissioner

Section 20. Returns shall be open to the inspection of the commissioner, and his deputies, assistants and clerks when acting under his authority. The books, accounts and other records in the hands of the commissioner, except returns, shall be open to the inspection of the state auditor, and his deputies, assistants and clerks when acting under his authority for the purpose of auditing the accounts of the commissioner.