1749-51 Mass. Acts 339

If any persons to the number of twelve or more, being armed with clubs or other weapons, or if any number of persons consisting of fifty or upwards, whether armed or not, shall be unlawfully, riotously, or tumultuously assembled; any Justice of the peace, field-officer or captain of the militia, sheriff of the county or under-sheriff, or any constable of the town, shall among the rioters, or as near to them as he can safely come, command silence while proclamation is making, and shall openly make proclamation in these or the like words, "Our Sovereign Lord the KING, chargeth and comandeth all persons, being assembled, immediately to disperse themselves, and peaceably to depart to their Habitations, or to their lawful Business, upon the pains contained in the Act of this Province made in the twenty-fourth year of his majesty King George the Second, for preventing and suppressing riots, routs, and unlawful assemblies. God save the King!"" [...] It shall be lawful for every such officer or officers, and for such other persons as he or they command to be assisting, to seize such persons, and carry them before a justice of the peace; and if such persons shall be killed or hurt by reason of their resisting the persons so dispersing or seizing them, the said officer or officers and their assistants shall be indemnified and held guiltless. [...]