Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 41, § 98D

Each city or town shall issue to every full-time police officer employed by it an identification card bearing the officer’s photograph and identifying information. The secretary of public safety and security may adopt regulations relative to the form, content and issuance of such identification cards and to the carrying thereof by municipal police officers. Such identification card shall be carried on the officer’s person and shall be exhibited upon lawful request for purposes of identification.