Tenn. Code Ann. § 41-1-107: Examination of witnesses

(a) The commissioner of correction is authorized to summon any witness or witnesses to appear before the commissioner to testify under oath in regard to any matter touching or relative to either the main state penitentiary or branch prisons.

(b) The commissioner is given the right to administer the oath to all the witnesses so summoned, or the witnesses may be sworn before any officer authorized by law to administer oaths.