Massachusetts General Laws Part IV. Crimes, Punishments and Proceedings in Criminal Cases (Ch. 263-280) Ch. 276, § 2D

(a) A warrant that does not require a law enforcement officer to knock and announce their presence and purpose before forcibly entering a residence shall not be issued except by a judge and only if the affidavit supporting the request for the warrant: (i) establishes probable cause that if the law enforcement officer announces their presence their life or the lives of others will be endangered; and (ii) includes an attestation that the law enforcement officer filing the affidavit has no reason to believe that minor children or adults over the age of 65 are in the home, unless there is a credible risk of imminent harm to the minor or adult over the age of 65 in the home.

(b) A police officer executing a search warrant shall knock and announce their presence and purpose before forcibly entering a residence unless authorized by a warrant to enter pursuant to subsection (a).

(c) An officer shall not dispense with the requirements of subsections (a) and (b) except to prevent a credible risk of imminent harm as defined in section 1 of chapter 6E.

(d) Evidence seized or obtained during the execution of a warrant shall be inadmissible if a law enforcement officer violates this section.