Massachusetts General Laws Part IV. Crimes, Punishments and Proceedings in Criminal Cases (Ch. 263-280) Ch. 263, § 3

No action, except for use of excessive force, shall lie against any officer other than the arresting officer, by reason of the fact that, in good faith and in the performance of his duties, he participates in the arrest or imprisonment of any person believed to be guilty of a crime unless it can be shown that such other officer in the performance of his duties took an active part in the arrest or imprisonment as aforesaid, either by ordering or directing that said arrest or imprisonment take place or be made, or by actually initiating the making and carrying out of said arrest and imprisonment. No action, except for use of excessive force, shall lie against any bystander assisting an officer in making an arrest, at the request of the officer.