Mass. Gen. Laws ch. 277, § 70

A justice of a court of record may at any time order a witness for the commonwealth in a criminal case or in a case under sections fifty-two to sixty-four, inclusive, of chapter one hundred and nineteen, pending in such court to recognize, with or without sureties, to appear and testify at the next or any succeeding sitting of said court, and may issue a warrant to bring such witness before him to recognize as aforesaid; but a witness unable to procure sureties shall not on that account be committed to jail except in cases of felony.