Mass. Gen. Laws ch. 149 § 150
The attorney general may make complaint or seek indictment against any person for a violation of section 148. On the trial no defence for failure to pay as required, other than the attachment of such wages by trustee process or a valid assignment thereof or a valid set-off against the same, or the absence of the employee from his regular place of labor at the time of payment, or an actual tender to such employee at the time of payment of the wages so earned by him, shall be valid. The defendant shall not set up as a defence a payment of wages after the bringing of the complaint. An assignment of future wages payable weekly under section one hundred and forty-eight shall not be valid if made to the person from whom such wages are to become due or to any person on his behalf, or if made or procured to be made to another person for the purpose of relieving the employer from the obligation to pay weekly. A loan made by an employee to his employer of wages which are payable weekly under section one hundred and forty-eight, whether made directly to the employer or to another person or persons on his behalf, shall not be valid as a defense on the trial of a complaint for failure to pay such wages weekly, unless such loan shall have been made with the approval of the attorney general.
An employee claiming to be aggrieved by a violation of sections 33E, 52E, 148, 148A, 148B, 148C, 150C, 152, 152A , 159C or 190 or section 19 of chapter 151 may, 90 days after the filing of a complaint with the attorney general, or sooner if the attorney general assents in writing, and within 3 years after the violation, institute and prosecute in his own name and on his own behalf, or for himself and for others similarly situated, a civil action for injunctive relief, for any damages incurred, and for any lost wages and other benefits provided, however, that the 3 year limitation period shall be tolled from the date that the employee or a similarly situated employee files a complaint with the attorney general alleging a violation of any of these sections until the date that the attorney general issues a letter authorizing a private right of action or the date that an enforcement action by the attorney general becomes final. An employee so aggrieved who prevails in such an action shall be awarded treble damages, as liquidated damages, for any lost wages and other benefits and shall also be awarded the costs of the litigation and reasonable attorneys fees.
Mass. Gen. Laws ch. 149, § 150