Tennessee Code Title 67. Taxes and Licenses § 67-1-306

(a) All the agents and assistants appointed by the board have full power to administer oaths, take affidavits and depositions, and otherwise exercise all powers necessary to gather evidence by compelling the attendance of witnesses, the production of books and papers, and exercising all the powers of commissioners or clerks of courts in taking depositions.

(b) The agents and assistants appointed by the board may issue subpoenas for witnesses and place them in the hands of any executive officer of any county whose duty it shall be to immediately execute the subpoenas and make due return of the subpoenas.

(c) Any assistant appointed by the board to gather such evidence shall not receive any fee or emolument other than the assistant's agreed salary and actual necessary expenses.

(d) Witnesses and sheriffs or constables executing process shall receive the same compensation as is fixed by law for like service in a court of record.