Supreme Judicial Court, May 13, 2013

When a mutual aid agreement is in place between jurisdictions under G.L. c. 37, § 13, an officer has full police powers in that other  jurisdiction when “circumstances arise dictating an immediate response or action for the good of public safety.”  Extraterritorial police action may be justified when an officer is acting to preserve the peace, even if no mutual aid agreement was in place at the time.