Mo. Rev. Stat. § 456.009: Lessor liable for double amount of deposit so held in trust, when.

Any person, firm or corporation being a trustee, as provided in section 456.007, who shall violate any of the provisions thereof, shall pay to the depositor a sum of money double the amount of the deposit or advance payment, which may be recovered in any court of competent jurisdiction, together with a reasonable attorney's fee to be fixed by the court and collected as other costs in the case. Any waiver or attempt to waive the provisions of section 456.007 and this section shall be void.