Mass. Gen. Laws ch. 263, § 7: Acquittal; effect on subsequent charges

Section 7. A person shall not be held to answer on a second indictment or complaint for a crime of which he has been acquitted upon the facts and merits; but he may plead such acquittal in bar of any subsequent prosecution for the same crime, notwithstanding any defect in the form or substance of the indictment or complaint on which he was acquitted.