Every judge of the district court, when it appears that any offense has been committed in connection with the trial of any cause, shall direct the county attorney to make a complete investigation, and to report to the judge fully and expeditiously the result of that investigation. If convinced that the interests of justice require, the judge shall direct that such report be made in writing and filed with the clerk of the district court and by him made a part of the records of the court. If the judge is satisfied that further action should be taken, he shall direct the county attorney to prosecute the party or parties who appear to have committed the offense, and it shall be the duty of the county attorney thereupon to proceed promptly with such prosecution. The county attorney in such proceedings may file an information verified on information and belief; Provided, where the judge is himself satisfied from what has occurred in the trial that a prosecution should be instituted, it shall be his duty to promptly order it without waiting for an investigation by the county attorney.