Chapter 276 of the General Laws, as appearing in the 2006 Official Edition, is hereby amended by inserting after section 2C the following section:-

   Section 2D. (a) A police officer executing a search warrant shall knock and announce his presence and purpose before forcibly entering a residence.

   (b) An officer may dispense with the requirement of subsection (a) if the officer has a reasonable suspicion that an announced entry will jeopardize the safety of officers or others, permit the destruction of evidence, or allow an occupant of the residence to escape.

   (c)  A search warrant shall authorize an officer to dispense with the requirement of subsection (a) if an affidavit discloses a reasonable suspicion that an announced entry will jeopardize the safety of officers or others, permit the destruction of evidence, or allow occupants of the residence to escape.  When executing such a search warrant, an officer shall not be required to reappraise his suspicions at the time of the search.

   (d) Evidence seized under subsections (b) and (c) shall be suppressed if subsequent judicial review determines that the officers lacked the requisite reasonable suspicion.