A police officer shall be considered "on duty" while on any assignment approved by the chief of the police department of the municipality he or she serves, whether the assignment is within or outside the municipality.
The Fund may take appropriate steps to verify the applicant's disability and earnings status, and for this purpose may request from the Department of Revenue a certified copy of the applicant's Illinois income tax return for any year for which a benefit under this Section is payable or has been paid.
The annual increase shall accrue on each anniversary of the initial pension payment date, for so long as the pension remains payable to the disabled police officer and the required annual application is made, except that the annual increases under this subsection shall cease if the disabled police officer earns income from gainful employment. Within 60 days after accepting an initial application under this subsection, the Fund shall pay to the disabled police officer, in a lump sum without interest, the amounts resulting from the annual increases that have accrued retroactively.
This subsection is not limited to persons in active service on or after its effective date, but it applies only to a pension that is payable under this Section to a disabled police officer (rather than a survivor). Upon the death of the disabled police officer, the annuity payable under this Section to his or her survivors shall include any annual increases previously received, but no additional increases shall accrue under this subsection.
40 ILCS 5/3-114.1