In a post-conviction retrospective competency hearing, placing the burden on the defendant to prove his incompetence by a preponderance of the evidence does not violate due process. Appellant was convicted of murder and sentenced to life without the possibility of parole. In Ary I , the appellate court held that the trial court erred by failing to conduct a pretrial inquiry into appellant’s competence to stand trial. Despite finding the error “per se prejudicial,” the court did not reverse the conviction. Rather, it remanded the matter to the trial court for a retrospective competency hearing and directed that the judgment be reversed only if appellant were found to have been incompetent to stand trial. On remand, the trial court found that it would be feasible to determine appellant’s competence when he was tried and ordered the competency hearing, with appellant bearing the burden of proving, by a preponderance of the evidence, that he was incompetent to stand trial. (Two years later, in People v. Young (2005) 34 Cal.4th 1149, 1217, the Supreme Court ruled that where a full competence hearing is required but the trial court fails to hold one, the judgment must be reversed.) The due process clause of the federal Constitution’s Fourteenth Amendment prohibits trying a criminal defendant who is mentally incompetent. Penal Code section 1368, et seq., requires the court to suspend criminal proceedings if it has a doubt regarding the mental competence of a defendant. With mental competency proceedings made during the pendency of the action and prior to judgment, a defendant has the burden of proving incompetence to stand trial. In this case, the majority of the appellate court in the second appeal, found that assigning the burden to the defendant is inconsistent with due process. But the Supreme Court agreed with the dissent and ruled that under the reasoning of Medina v. California (1992) 505 U.S. 437, a state is free to allocate the burden of proving mental incompetence at any stage in the proceedings, including a retrospective competency hearing and, if a post-conviction competency hearing is feasible, there is no due process violation by placing the burden of proving incompetence on the defendant.