§43A-1-108.

§43A-1-108.
   
   Anyone in custody as a person in need of treatment or a child in need
   of mental health treatment, pursuant to the provisions of this title,
   is entitled to a writ of habeas corpus, upon a proper application made
   by him or some relative or friend in his behalf pursuant to the
   provisions of Sections 1331 through 1355 of Title 12 of the Oklahoma
   Statutes. Upon the return of such writ, the fact of his mental illness
   shall be inquired into and determined. Notice of hearing on said writ
   must be given to the guardian of such patient, if one has been
   appointed, to the person who applied for the original commitment and
   to such other persons as the court may direct. The medical or other
   history of the patient, as it appears in the institutional record,
   shall be given in evidence, and the superintendent of the institution
   wherein such person is held in custody, and any proper person, shall
   be sworn touching the condition of such person.
   
   The superintendent shall make available for examination by physicians
   selected by the person seeking the writ, the patient whose freedom is
   sought by writ of habeas corpus. Any evidence, including evidence
   adduced in any previous habeas corpus proceedings, touching upon the
   mental condition of the patient shall be admitted in evidence.