A. The board may compel witnesses to attend and testify on any matter pertaining to this article, and its president or any member may administer oaths. The board may provide for payment of its necessary expenses, except that no compensation is payable to members of the board for duties performed under this article.

B. Funds that are not immediately required for the payment of pensions or benefits under this article may be invested or reinvested, at the discretion of the board of trustees, by the county treasurer or by the board of trustees, as follows:

1. In bonds of the United States.

2. In federal housing insured mortgage bonds of the United States.

3. In federal land bank bonds.

4. Any bonds on which the payment of interest and principal is guaranteed by the United States.

5. Bonds issued by any United States government instrumentality or federal agency that qualify and are acceptable as security for public funds of the United States government.

6. General obligation bonds of this state or of the counties, incorporated cities and towns and school districts of this state.

7. Revenue bonds of the incorporated cities and towns of this state, the Arizona board of regents, the Arizona power authority or any other legally constituted state authority or agency authorized by law to issue revenue bonds, except revenue bonds for recreational purposes issued by cities and towns.

8. Bonds of agricultural improvement districts and agricultural improvement and power districts organized under the laws of this state when issued or guaranteed, with the approval of the secretary of the interior, by corporations operating a United States reclamation project within the state.

9. Bonds of incorporated cities or towns of this state issued under sections 48-595, 48-596, 48-597, 48-598, 48-599, 48-600, 48-601, 48-602, 48-603, 48-604, 48-605, 48-606, 48-607, 48-608, 48-609, 48-609.01 and 48-610.

10. First lien bonds of sanitary districts issued pursuant to Title 48, Chapter 14.

11. Registered warrants of the state, or registered county or school district warrants when offered as security for monies of the county or school district by which they are issued.

12. Interest-bearing savings accounts or certificates of deposit in banks doing business in this state whose accounts are insured by the federal deposit insurance corporation, but only if such deposits in excess of the insured amount are secured by the depository to the same extent and in the same manner as required by the general depository law of the state.

13. Interest-bearing savings accounts or certificates of deposit in savings and loan associations doing business in this state, whose accounts are insured by the federal savings and loan insurance corporation, but only if such deposits in excess of the insured amount are secured by the depository to the same extent and in the same manner as required by the general depository law of this state.

14. Deposits placed in accordance with the procedures prescribed in Section 35-323.01.

C. All matters pertaining to the benefits granted by this article to firefighters and their dependents shall be presented to the board, and any person aggrieved by a decision of the board, at any time within thirty days after its decision, may petition for a writ of certiorari, and the court may on final hearing reverse or affirm, wholly or partly, or may modify, the decision reviewed.