No interest of any person in any pension fund or in any pension derivable therefrom, for the benefit of police officers or firefighters, now or hereafter created or held by authority of law by any city or town, or by any public officer or officers or board of officers therein, to which fund the city or town contributes in any way, shall be subject to trustee process or liable to attachment on any writ, original, mesne, or judicial, or be taken on execution or any process, legal or equitable; and no assignment of any such interest shall be valid.
R.I. Gen. Laws § 9-26-5