Tenn. Code Ann. § 67-1-1006: Obtaining evidence

(a) The officials having power to back assess or reassess property are vested with full authority to administer oaths, send for and examine witnesses, and take such steps as may be deemed necessary or material to obtain information and evidence as to the value of the property.

(b) Such witnesses, when properly summoned, shall be amenable to existing laws for nonattendance or failure to give evidence that is in their knowledge.