The board of trustees of police and firemen’s pension systems, established under the provisions of section 86.583, may invest and reinvest the moneys of the system, and may hold, purchase, sell, assign, transfer or dispose of any of the securities and investments in which such moneys shall have been invested, as well as the proceeds of such investments and such moneys. The board of trustees of police and firemen’s pension systems, established under the provisions of section 86.583, shall invest the funds of the system as permitted by sections 105.687 to 105.690.