Every police officer and fire fighter of any city or town who served the city or town for at least twenty-five (25) years, or is now or hereafter receiving a retirement allowance from a city or town retirement system after at least twenty-five (25) years' membership in a system prior to retirement, or who was retired by a city or town retirement system because of a disability incurred as the result of an accident while in the performance of duty, may receive from the city or town an additional sum of money, assuring to the employee the sum of two hundred and fifty dollars ($250) per month.
R.I. Gen. Laws § 45-19-18