Mo. Rev. Stat. § 414.550
The director may make such investigations as the director deems necessary to carry out effectively the director's responsibilities under sections 414.500 to 414.590 or to determine whether a person has engaged or is engaging in any acts or practices that constitute a violation of any provision of sections 414.500 to 414.590 or of any regulation or plan issued under sections 414.500 to 414.590. For the purpose of any investigation, the director is empowered to administer oaths and affirmations, subpoena witnesses, compel their attendance, take evidence, and require the production of any books, papers, and documents which are relevant to the inquiry. Such attendance of witnesses and the production of any such records may be required from any place in the state. In case of contumacy by, or refusal to obey a subpoena issued to, any person, the director may seek enforcement thereof in the circuit court of proper venue.
§ 414.550, RSMo