The Commissioner shall have the power to administer oaths, subpoena witnesses, and order the production of books and papers pertinent to any investigation or hearing authorized by this chapter. (Amended 1959, No. 331 (Adj. Sess.), § 9, eff. Feb. 9, 1960; 1969, No. 113, § 5; 1981, No. 249 (Adj. Sess.), § 26, eff. July 4, 1982.)