Mont. Code Ann. § 2-15-504

The attorney general shall review a complaint referred from a county attorney concerning alleged misconduct of a local government public officer pursuant to 7-4-2718 or an independent complaint made to the attorney general concerning the alleged misconduct of a local government public officer and any evidence concerning the officer's alleged misconduct. After reviewing the complaint, the attorney general may instruct the county attorney to diligently prosecute the officer as provided by 2-15-501 (5), bring an action against the officer as provided in 45-7-401, or decline to prosecute the officer.