Mo. Rev. Stat. § 416.455: Person injured by violation may intervene in or bring injunction action.

Any person who is injured in business or property by reason of another person's violation of any provision of sections 416.410 to 416.560 may intervene in the suit for injunction instituted pursuant to section 416.450 against the other person or he may bring a separate action and recover three times the actual damages sustained as a result of the violation, together with the costs of the suit, or may sue to enjoin the violation of any provision of sections 416.410 to 416.560.