Okla. Stat. tit. 74, § 18d

The Attorney General shall have authority to require the aid and assistance of district attorneys in their respective counties in the matters hereinbefore enumerated and may in any case brought to the Supreme Court or Criminal Court of Appeals from their respective counties demand and receive the assistance of the district attorney from whose county such case is brought. Any district attorney desiring the assistance of the Attorney General in any matter shall request the Governor for such assistance, and upon receiving the direction of the Governor to render such assistance, the Attorney General shall proceed immediately, compatible with the performance of his own duties to render the assistance. Laws 1939, p. 46, § 5.