A. The supreme court shall review all death sentences. On review, the supreme court shall independently review the trial court's findings of aggravation and mitigation and the propriety of the death sentence.
B. If the supreme court determines that an error was made regarding a finding of aggravation or mitigation, the supreme court shall independently determine if the mitigation the supreme court finds is sufficiently substantial to warrant leniency in light of the existing aggravation. If the supreme court finds that the mitigation is not sufficiently substantial to warrant leniency, the supreme court shall affirm the death sentence. If the supreme court finds that the mitigation is sufficiently substantial to warrant leniency, the supreme court shall impose a life sentence pursuant to section 13-751, subsection A.
C. The independent review required by subsection A does not preclude the supreme court from remanding a case for further action if the trial court erroneously excluded evidence or if the appellate record does not adequately reflect the evidence presented.