The fiscal officer of the board of library trustees of a free public library shall be the treasurer of the library funds. All moneys received by the fiscal officer for library purposes shall be immediately placed by the fiscal officer in a depository designated by the board. The fiscal officer shall keep an account of the funds credited to the board. The fiscal officer shall render a statement to the board monthly showing the revenues and receipts from whatever sources derived, the disbursements and the purposes for such disbursements, and the assets and liabilities of the board. At the end of each fiscal year the fiscal officer shall submit to the board a complete financial statement showing the receipts and expenditures in detail for the entire fiscal year. The board of library trustees of a free public library may appoint a deputy fiscal officer, for a term of one year, and may authorize such deputy to receive and disburse library funds. Such deputy, before entering upon official duties, shall execute a bond in an amount and with surety to be approved by the board, payable to the board, and conditioned for the faithful performance of the official duties required of the deputy.