R.I. Gen. Laws § 28-17-4: Immunity from attachment, process, or assignment.

The interest of any person in any employees’ trust as defined in § 28-17-1 and any pension derivable from that trust shall not 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 interest or pension shall be valid.