40 ILCS 5/5-189
To authorize the payment of any annuity, pension, or benefit granted under this Article or under any other Act relating to police pensions, heretofore in effect in the city which has been superseded by this Article; to increase, reduce, or suspend any such annuity, pension, or benefit whenever any part thereof was secured or granted or the amount thereof fixed, as the result of misrepresentation, fraud, or error; provided, the annuitant, pensioner or beneficiary concerned shall be notified and given an opportunity to be heard concerning such proposed action.
The Board shall have exclusive original jurisdiction in all matters relating to or affecting the fund, including, in addition to all other matters, all claims for annuities, pensions, benefits or refunds.
40 ILCS 5/5-189