Mo. Rev. Stat. § 56.445: Circuit attorney and assistants to devote full time to office — special assistants may engage in civil practice (St. Louis City).

It shall be the duty of the circuit attorney of the City of St. Louis and of his assistants and associates to devote their entire time and energy to the discharge of their official duties; but the circuit attorney may in his discretion designate as many as seven of his assistants as provided for in section 56.540 as special assistant circuit attorneys and those special assistant circuit attorneys may be allowed to engage in the civil practice of law.