It shall be the duty of every grand jury to investigate and make diligent inquiry concerning any alleged misconduct or incompetency of any public officer in the county which may be brought to its notice; and, if, on such investigation and inquiry, it finds that such officer, for any cause mentioned in this chapter, ought to be removed from office, it shall so report to the court, setting forth the facts, which report shall be entered on the minutes of the court. If the officer so reported against is one of those included in Section 174, Article 7, of the constitution, the clerk of the court shall transmit a certified copy of such report to the Attorney General. If the officer so reported against is the presiding judge of the court, the report must not be made to the court or entered on the minutes; and, in such cases, the report of the grand jury must be signed by the foreman and countersigned by the district attorney, who must transmit the same to the Attorney General.