Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 125, § 3

All other officers and all employees in the said institutions shall be appointed by the commissioner, and, except as otherwise provided in chapter thirty and thirty-one, shall hold office during his pleasure. The duties of a correction officer or correctional program officer shall include the duty to transport inmates outside of a correctional facility and to prevent their escape, and no special state police officer appointment under section 127 of chapter 127 shall be necessary for such purposes.