Mass. Gen. Laws ch. 279 § 59
The sentence of death shall be executed by the superintendent of the state prison, or by a person acting under his direction, not earlier than twenty days nor later than thirty days after service upon said superintendent, or officer performing his duties, of a certificate of the clerk of the court that the stay of the execution of the sentence has been revoked under section four, unless the governor pardons the crime, commutes the punishment therefor or respites the execution or said execution is otherwise delayed by process of law. If the execution is respited or stayed by process of law, the sentence of death shall be executed within the week beginning on the day next after the day on which the term of respite or stay expires. The sentence of death shall be executed upon such day within the limits of time provided in this section as the superintendent elects; but no previous announcement thereof shall be made, except to such persons as may be permitted to be present in accordance with section sixty-five.
Mass. Gen. Laws ch. 279, § 59