Section 83B. The commissioner may remove to any camp so established any prisoner held in a correctional institution of the commonwealth except the Massachusetts Correctional Institution, Framingham, and sentenced prisoners in jails and houses of correction, including male prisoners sentenced to life who have served twelve years, except a prisoner serving a life sentence for first degree murder, or a sentence imposed for violation of sections twenty-two, 22A, 22B, 22C, twenty-three, 23A, 23B and twenty-four of chapter two hundred and sixty-five and for attempt to commit a crime referred to in said sections, who, in his judgment, may properly be so removed and may at any time return such prisoners to the prison from whence removed. Prisoners so removed shall be entitled to a permit to be at liberty as provided under the provisions of sections one hundred and twenty-eight, one hundred and thirty-two and one hundred and thirty-three of chapter one hundred and twenty-seven.
If a prisoner escapes or attempts to escape from a prison camp all deductions from the sentence he is then serving shall be thereby forfeited. A prisoner who is entitled to have the term of his imprisonment reduced shall receive from the parole board a certificate of discharge and shall be released from the prison camp on the date which has been determined by such additional deduction from the maximum term of his sentence or sentences.