Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 140, § 164

A person who owns or keeps a dog and who has received such notice under section 163 and does not, within 24 hours, euthanize the dog or thereafter keep it on the owner's or keeper's premises or under the immediate restraint and control of some person, shall be punished by a fine of not less than $25 and a police officer, constable or animal control officer may euthanize the dog in a humane manner if it is found outside the enclosure of its owner or keeper and not under the owner or keeper's immediate care.