A mayor, alderman, selectman, justice of the peace, sheriff or deputy sheriff who, having notice of any such riotous or tumultuous and unlawful assembly in the city or town where he lives, neglects or refuses immediately to proceed to the place of such assembly, or as near thereto as he can with safety, or omits or neglects to exercise the authority conferred upon him by this chapter for suppressing such assembly and for arresting the offenders, shall be punished by a fine of not more than three hundred dollars.
Massachusetts Legal Code