Okla. Stat. tit. 19, § 19-545: Service of district court work or other court work

All work issued out of the district court shall be served by the

sheriff or his salaried deputies, together with such other work as

may be placed in the hands of the sheriff or salaried deputies, by

any court in his or their county except as provided in Section 158.1

of Title 12 of the Oklahoma Statutes. All process placed in the

hands of the said sheriff shall be served promptly and the return

thereof made without delay and filed in the proper court. A failure

to promptly serve process placed in the hands of the sheriff, or the

failure to perform expeditiously all the duties of his office, shall

be grounds for removal of such sheriff.