The state has the burden of proving the mental competence of the defendant by a preponderance of the evidence

A defendant is mentally competent to be executed if the defendant is aware of the impending execution and the reason for it. If the defendant has previously been determined to be competent to be executed under this chapter and there is a subsequent motion to the sentencing court that the defendant no longer appears to be mentally competent to be executed, there shall be a prima facie showing of a substantial change in circumstances raising a significant question of the defendant's competence to be executed before the sentencing court conducts any further hearing. Source: SL 2008, ch 117 , § 10.