Section 4. Sentence shall be imposed upon conviction of a crime, regardless of whether an appeal has been taken, except as otherwise provided in section sixty-one in case of a conviction of a capital crime.
If sentence is imposed upon conviction of a crime punishable by death, the justice imposing the sentence shall at the same time stay the execution of the sentence, such stay to be effective until revoked by the superior court department of the trial court, which is hereby granted full powers of revocation in the premises. The clerk of such court shall, forthwith upon the revocation by the court of any such stay of execution of sentence, certify that said stay has been revoked and cause said certificate to be served upon the superintendent of the state prison, or the officer performing his duties, by any officer qualified to serve criminal process; and the officer serving the same shall forthwith make due return of service to the clerk.