Mont. Code Ann. § 7-32-4103

The mayor in all cities and towns or the manager in those cities operating under the commission-manager plan has charge of and supervision over the police department. The mayor or manager shall appoint all the members and officers of the department. Subject to the provisions of this part, the mayor or manager may suspend or remove any member or officer of the force. The mayor or manager shall make rules, not inconsistent with the provisions of this part, the other laws of the state, or the ordinances of the city or town council, for the government, direction, management, and discipline of the police force.