(1) In a civil action for damages for personal injury, wrongful death, or property damage, it is an affirmative defense that such action arose from an injury or damage sustained by a participant acting in furtherance of a riot. The affirmative defense authorized by this section shall be established by evidence that the participant has been convicted of a riot or an aggravated riot prohibited under s. 870.01, or by proof of the commission of such crime by a preponderance of the evidence. (2) In a civil action in which a defendant raises an affirmative defense under this section, the court must, on motion by the defendant, stay the action during the pendency of a criminal action that forms the basis for the defense, unless the court finds that a conviction in the criminal action would not form a valid defense under this section.