Any citizen of the state may appear at the hearing provided for in this chapter and shall be heard in favor of or in opposition to the petition. The attorney general, if the attorney general has reason to believe that the petitioner is not a bona fide citizen of the state of North Dakota or of the United States of America, shall appear at the hearing in opposition to the petition. The attorney general, if the attorney general has any doubt relative to the citizenship of the petitioner, shall secure any information required for such hearing from any department of the government of the United States of America. The state’s attorney of the county in which the proceeding is pending shall appear at any hearing on a petition filed under the provisions of this chapter.