Upon the death of a member or annuitant, the following amount shall be payable (i) to a beneficiary nominated by written designation of the member or annuitant filed with the system, or (ii) if no beneficiary is nominated, to the surviving spouse, or (iii) if no beneficiary is nominated and there is no surviving spouse, to the decedent's estate, upon receipt of proper proof of death:
(1) Upon the death of a member, an amount consisting of the sum of the following: (A) the member's accumulated contributions; (B) the sum of the contributions made by the member toward the cost of the automatic increase in annuity under Section 16-152, without interest thereon; and (C) contributions made by the member toward prior service, without interest thereon.(2) Upon the death of an annuitant, unless a reversionary annuity is payable under Section 16-136, an amount determined by subtracting the total amount of monthly annuity payments received as a result of the deceased annuitant's retirement from the sum of: (A) the accumulated contributions at retirement; (B) the sum of the contributions made by the deceased toward the cost of the automatic increase in annuity under Section 16-152, without interest thereon; and (C) any contributions made by the deceased for prior service or other purposes, exclusive of contributions toward the cost of the automatic increase in annuity, without interest thereon.P.A. 83-1440; 91-887, eff. 7/6/2000; 92-16, eff. 6/28/2001.