Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 51, § 47B

If at any time subsequent to the registration of a voter the registrars have probable cause to believe that the voter has made a false statement in his affidavit of registration, they may prepare a complaint setting forth the basis for their belief, and summon the voter to appear before them in the manner set forth in section forty-eight. They shall examine the voter and determine his qualifications to vote in the manner set forth in section forty-nine.