Mass. Gen. Laws ch. 147 § 2
All inspectors of the office of public safety and inspections of the division shall have and exercise throughout the commonwealth the powers of constables, police officers and watchmen, except as to the service of civil process. The governor may command their services in suppressing riots and in preserving the peace. The commissioner may request the colonel of state police to appoint such inspectors as special state police officers and invest them with such of the powers of the state police officers as said colonel may deem advisable. The commissioner, with the approval of the governor, may authorize the inspectors of the office of public safety and inspections of the division to carry badges, revolvers, clubs, handcuffs and twisters, or such other articles as may be required in the performance of their duties.
Mass. Gen. Laws ch. 147, § 2