(a) The several assistant district attorneys general and/or criminal investigators in all districts shall be reimbursed from funds appropriated to the office of the district attorney general in the district in which they are employed for the necessary traveling expenses incurred while upon official business as prescribed under the comprehensive travel regulations for employees of the state; provided, that reimbursement to such officials for necessary traveling expenses incurred while on official business within the county of their residence shall be limited to reimbursement of mileage expense; and provided further, that any subsequent changes in the amounts or types of reimbursable expenses as prescribed under the comprehensive travel regulations then shall apply automatically, and without further action, to the several assistant district attorneys general and/or criminal investigators at such times as changes become effective as to employees of the state.

(b) All expense accounts submitted by any assistant district attorney general or criminal investigator shall be submitted upon forms provided and prescribed by the judicial cost accountant. In addition thereto, such expense accounts shall be submitted during the month following the month in which the expense was incurred, and all such expense accounts must be verified by such assistant or criminal investigator and the same shall likewise be first approved by the district attorney general of the judicial district. If any person fails to comply with this section, this expense account shall be disallowed and the same shall not be paid.