Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 41, § 30

Any person chosen to determine the valuation of property for the purpose of taxation who, in order that the taxpayers may escape payment of their just proportion of any state or county tax or in order to evade any law limiting municipal indebtedness or the rate of taxation to a percentage of valuation or for any other fraudulent or corrupt purpose, knowingly fixes the valuation of any property at a smaller or greater amount than its full and fair cash value, or who causes an abatement to be made otherwise than is provided by law, shall be punished by a fine of not more than one thousand dollars, or by imprisonment for not more than six months, or both.