Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 149, § 177

A person may, if his property is in danger, call upon the regular police authorities in the commonwealth for assistance in its protection, and this and the preceding section shall not limit or diminish such right; but no person shall request or authorize any person or body of persons not residents of the commonwealth, except regular employees, to assist such person with arms in the defence of his property, and no such request or authority shall justify an assault or attack with arms by a non-resident. Whoever, being an employer of labor, requests or authorizes assistance in violation of this section, and whoever renders such assistance with arms, shall be severally liable in damages to each person injured in person or property thereby.