Any qualified elector of the county shall have the right to contest the right of any person whose name is subscribed to such petition to file the same, or to contest said petition as to any name or names subscribed thereto which he believes are fictitious: provided, he shall, within ten (10) days after such petition is filed, file in the office of the clerk a list of the names of the persons whose right to sign such petition he is desirous of contesting and/or a list of the names therein which he believes to be fictitious, together with an affidavit attached thereto stating specifically the grounds of his contest.
Idaho Code § 31-405