After trial is commenced, at any time prior to the rendering of a verdict, the court may declare a mistrial on its own motion or on motion of any party if it determines an occurrence at trial has prevented a fair trial. If the court determines that the deliberate misconduct of a party or an attorney caused a mistrial, the court may require the party or the attorney, or both, to pay the reasonable expenses including attorney fees incurred by the opposing party or parties resulting from the misconduct.