If the petition is filed by a citizen or by an organization, it shall not be dismissed by the complainant or for want of prosecution except upon a sworn statement by the complainant or the complainant’s attorney, setting forth the reasons why the suit should be dismissed, and the dismissal ordered by the court. In case of failure to prosecute any such suit with reasonable diligence, or at the request of the complainant, the court, in its discretion, may substitute any other citizen or organization, including, but not limited to the attorney general or the prosecutor or prosecuting attorney of the county consenting thereto for the complainant. If a suit is brought by a citizen or by an organization and the court finds that there was no reasonable ground or cause therefor, the costs shall be taxed against such citizen or organization, except that no costs shall be taxed against state or county organizations.