They may serve by copy, by them attested, demands, notices and citations not required by law to be served by an officer, and their returns of service thereof shall be prima facie evidence.
Mass. Gen. Laws ch. 37, § 12
Duties of sheriffs and deputies; service of demands, notices and citations
Official source: Massachusetts Legislature. Reproduced from public-domain Massachusetts statutes; confirm against the official source for the current text. Not legal advice.