Mass. Gen. Laws ch. 234A, § 68C: Failure of jury to agree

Section 68C. If a jury, after due and thorough deliberation, returns to court without having agreed on a verdict, the court may state anew the evidence or any part of the evidence, explain to them anew the law applicable to the case and send them out for further deliberation; but if they return a second time without having agreed on a verdict, they shall not be sent out again without their own consent, unless they ask from the court some further explanation of the law.