40 ILCS 5/17-123
If a teacher dies (a) in service, (b) after resignation or (c) after retirement but before receiving any pension payment, his or her estate shall be paid a refund of the amounts he or she contributed to the Fund less (1) any former refund that has not been repaid, (2) the amount contributed for a survivor's pension in the event such pension is payable under Sections 17-121 and 17-122 and (3) pension payments received; but if a written direction, signed by the contributor before an officer authorized to take acknowledgments and stating that the refund shall be paid to named beneficiaries, was filed with the Board prior to his or her death, the refund shall be paid to such named beneficiaries. If any of several named beneficiaries does not survive the contributor and no directive was furnished by the member to cover this contingency, the deceased beneficiary's share of the refund shall be paid to the estate of the contributor.
In addition to the payment provided in the foregoing paragraph, if such teacher has received service credit within 13 calendar months of the date of death or was on a sick leave authorized by the Employer at the time of death, and if no other pensions or benefits were payable under the provisions of this Article or any other participating system, as defined in the Illinois Retirement Systems Reciprocal Act, except a refund of contributions or a survivor's pension, there shall be paid a single payment death benefit. For a teacher who dies on or after the effective date of this amendatory Act of 1991, this benefit shall be equal to the last month's base rate of salary, subject to the limitations and conditions set forth in this Article, for each year of validated service, not to exceed 6 times such salary, or $10,000, whichever is less. The single payment death benefit shall be paid in the manner prescribed for a refund of contributions to the Fund.
Death benefits shall be paid only on written application to the Board.
40 ILCS 5/17-123