An inmate serving a sentence who is transferred to Atascadero State Hospital for treatment of mental illness, remains “confined in a state prison,” such that he may be prosecuted for in-prison offenses. While serving a prison sentence, appellant was transferred to Atascadero State Hospital for mental health care treatment pursuant to Penal Code section 2684. During the intake process, he struck a nurse in the face and was subsequently charged with and convicted of felony battery on a non prisoner (Pen. Code, sec. 4501.5). The appellate court found the conviction to be a legal impossibility because appellant was not confined in prison, as required by section 4501.5. The Supreme Court noted that Penal Code section 4505, subdivision (b) which provides the definition of “confined in prison,” includes prisoners who are temporarily outside the prison walls for other purposes. Applying rules of statutory construction, the Court ruled that “other purposes” includes the prisoner who has been temporarily transferred to Atascadero State Hospital for treatment and reversed the appellate court judgment. (Disapproving People v. Superior Court (Ortiz) (2004) 115 Cal.App.4th 995.)