The county attorney has a duty to prosecute or defend all civil or criminal suits in which the state or county is a party or interested, on behalf of the state or county. The county attorney shall appear before any magistrate and conduct any criminal examination, prosecute all civil suits before any magistrate in which the state or county is a party or interested. When the county board or county officers request opinions or advice concerning duties of the offices or matters in which the state or county may have an interest, the county attorney shall give opinions or advice for no fee. The county attorney shall perform all duties enjoined by law upon the county coroner and shall be ex officio county coroner.