Mo. Rev. Stat. § 86.520

The board shall have exclusive control and management of funds created for the purpose herein and of all moneys donated, paid or received for the relief or pensioning of retired or disabled members of the police department, their widows and minor children, and may have an assessment from each member of at least five percent but not more than ten percent of the salary of such member, the contribution to be placed by the treasurer to the credit of such fund, subject to the order of the board. The percent rate shall not be changed without the affirmative vote of a majority of the entire board.