Mass. Gen. Laws ch. 41 § 97A
In any town which accepts this section there shall be a police department established by the selectmen, and such department shall be under the supervision of an officer to be known as the chief of police. The selectmen of any such town shall appoint a chief of police and such other officers as they deem necessary, and fix their compensation, not exceeding, in the aggregate, the annual appropriation therefor. In any such town in which such appointments are not subject to chapter thirty-one, they shall be made annually or for a term of years not exceeding three years, as the selectmen shall determine, and the selectmen may remove such chief or other officers for cause at any time after a hearing. The chief of police in any such town shall from time to time make suitable regulations governing the police department, and the officers thereof, subject to the approval of the selectmen; provided, that such regulations shall become effective without such approval upon the failure of the selectmen to take action thereon within thirty days after they have been submitted to them by the chief of police. The chief of police in any such town shall be in immediate control of all town property used by the department, and of the police officers, whom he shall assign to their respective duties and who shall obey his orders. Section ninety-seven shall not apply in any town which accepts the provisions of this section. Acceptance of the provisions of this section shall be by a vote at an annual town meeting.
Mass. Gen. Laws ch. 41, § 97A