(1) The district attorney of each judicial district is authorized to appoint a chief investigator and such other investigators as he may deem necessary in the conduct of his office and such stenographers, office employees, and other technical and professional assistants as are necessary to properly transact the business of his office. The salary and compensation in each instance for such employees and assistants shall be fixed by such district attorney in an amount commensurate with the services performed and the duties and responsibilities of such employees, subject to the approval of the board of county commissioners of the county or the city council of a city and county affected.
(2) The salaries of any personnel so appointed shall be paid by the various counties within the judicial district, each county paying its proportionate part of said salaries as the population of such county bears to the whole population of such judicial district, according to the last preceding federal census.