Mass. Gen. Laws ch. 44 § 53C
All money received by a city, town or district as compensation for work performed by one of its employees on an off-duty work detail which is related to the employee's regular employment or for special detail work performed by persons where such detail is not related to regular employment shall be deposited in the treasury and shall be kept in a fund separate from all other monies of such city, town or district and, notwithstanding the provisions of section fifty-three, shall be expended without further appropriation in such manner and at such times as shall, in the discretion of the authority authorizing such off-duty work detail or special detail work, compensate the employee or person for such services; provided, however, that such compensation shall be paid to such employee or person no later than ten working days after receipt by the city, town or district of payment for such services.
When necessary, a city, town or district may appropriate funds to be placed in the special fund authorized by this section to be used for the purpose for which the fund was established. A city, town or district may establish a fee not to exceed ten per cent of the cost of services authorized under this section, which shall, except in the case of a city, town, district or the commonwealth, be paid by the persons requesting such private detail. Any such fee received shall be credited as general funds of the city, town or district and shall not be used again without further appropriation.
Districts shall include regional school districts.
Mass. Gen. Laws ch. 44, § 53C