It is the duty of every prosecuting attorney to cooperate fully and promptly with persons seeking to apply for relief, including copetitioners with the department, under this article in all cases of suspected child abuse and neglect; to promptly prepare applications and petitions for relief requested by those persons, to investigate reported cases of suspected child abuse and neglect for possible criminal activity; and to report at least annually to the grand jury regarding the discharge of his or her duties with respect thereto.