At the end of each month, an officer who is compensated on a salary basis shall prepare a report of the officer's expenses. The report must:
(1) contain an itemized and sworn statement of all approved expenses incurred by the officer and charged to the officer's county;
(2) contain the name of the case, if any, in connection with which an expense is incurred; and
(3) be accompanied by invoices covering any purchases and requisitions issued by the officer and included in the report.