If the grantor dies or removes from the commonwealth without having acknowledged his deed, the due execution thereof may be proved before any court of record in this commonwealth by the testimony of a subscribing witness thereto.
Mass. Gen. Laws ch. 183, § 34
Proof of execution of deed by testimony of subscribing witness
Official source: Massachusetts Legislature. Reproduced from public-domain Massachusetts statutes; confirm against the official source for the current text. Not legal advice.