The court on motion of a defendant may grant a new trial to the defendant if required in the interest of justice. If trial was by the court without a jury, the court on motion of a defendant for a new trial may vacate the judgment if entered, take additional testimony and direct the entry of a new judgment. A motion for a new trial shall be made within 10 days after verdict or finding of guilty or within such further time as the court may fix during the 10-day period. The finding of guilty may be entered in writing or orally on the record.