Mo. Rev. Stat. § 537.360: Single damages only recoverable, when.

On the trial of any action or prosecution brought upon sections 537.340, 537.350 and 537.370 if it shall appear that the defendant had probable cause to believe that the land on which the trespass is alleged to have been committed, or that the thing so taken, carried away, injured or destroyed, was his own, the plaintiff in the action or prosecution shall receive single damages only, with costs.