The hearing of the motion to discharge shall be a trial of the issue of the existence, at the time of the issuance of the order, of one or more of the grounds of attachment listed in section 25-1001, as alleged in the affidavits under section 25-1002. The court shall discharge an order of attachment unless the plaintiff proves by a preponderance of the evidence one of the grounds alleged under section 25-1001 upon which the writ was issued. The court may order that the evidence at the hearing of the motion to discharge be presented, in whole or part, by affidavits in the form prescribed by section 25-1334, for affidavits in support of or in opposition to a motion for summary judgment. In all cases in which the court does not so order, evidence presented at the hearing of the motion to discharge shall be governed by the Nebraska Evidence Rules.