Massachusetts General Laws Part IV. Crimes, Punishments and Proceedings in Criminal Cases (Ch. 263-280) Ch. 278A, § 16

(a) Any governmental entity that is in possession of evidence or biological material that is collected for its potential evidentiary value during the investigation of a crime, the prosecution of which results in a conviction, shall retain such evidence or biological material for the period of time that a person remains in the custody of the commonwealth or under parole or probation supervision in connection with that crime, without regard to whether the evidence or biological material was introduced at trial. Each governmental entity shall retain all such evidence or biological material in a manner that is reasonably designed to preserve the evidence and biological material and to prevent its destruction or deterioration. The evidence or biological material need not be preserved if it is to be returned to a third party or if it is of such a size, bulk or physical character as to render retention impracticable.

(b) The director of the crime laboratory within the department of state police, in consultation with the forensic sciences advisory board established by section 184A of chapter 6, shall promulgate regulations governing the retention and preservation of evidence or biological material by any governmental entity. The regulations shall include standards for maintaining the integrity of the materials over time, the designation of officials at each governmental entity with custodial responsibility and requirements for contemporaneously recorded documentation of individuals having and obtaining custody of any evidence or biological material.