¶1concurring in part and dissenting in part.
¶2I would uphold the conviction of capital murder but commute the sentence of death to imprisonment for life.
¶3On appeal, defendant argued that the jury’s penalty verdict was ambiguous “and therefore violated his constitutional right to a unanimous verdict.” The majority refused to consider this argument on the grounds that defendant had not preserved the issue at trial and had not raised it by assignment of error on appeal. The majority misconceives the nature and scope of appellate review of the death penalty.
¶4Code § 17-110.1 commands this Court to “consider and determine . . . [wjhether the sentence of death is excessive or disproportionate to the penalty imposed in similar cases, considering both the crime and the defendant.” We must consider the disproportionality question “[i]n addition to consideration of any errors in the trial enumerated by appeal.” Id. The statutory command is absolute, the death-penalty review is automatic, and the disproportionality inquiry is not conditioned upon defense counsel’s compliance with rules governing appellate procedure in noncapital casesi We have only recently held that the waiver rule (i.e., that an error assigned is waived if not argued on appeal) does not apply to the penalty review mandated by Code § 17-110.1(C). Fitzgerald v. Commonwealth, 223 Va. 615, 639, 292 S.E.2d 798, 812 (1982). While I agree that the waiver rule, the contemporaneous *153objection rule, and Rule 5:21 apply to defendant’s appeal of his capital murder conviction, I believe their application to a determination of disproportionality vel non violates the statutory command.
¶5In making such a determination, we must conduct an independent survey of similar capital cases, compare the penalties imposed, and decide whether Virginia juries generally impose the death penalty in such cases. Stamper v. Commonwealth, 220 Va. 260, 283-84, 257 S.E.2d 808, 824 (1979). In order to conduct such a survey, we must be able to identify cases that are similar to the one at bar. Our task is impossible in this appeal.
¶6Code § 19.2-264.2 provides that “a sentence of death shall not be imposed” except upon certain findings of “aggravating circumstances” which have come to be called “the vileness predicate” and “the dangerousness predicate.” It is axiomatic that a jury’s verdict in a criminal case must be unanimous. Va. Const., art. I, § 8; Rule 3A:24(a). When the legislature conditions a penalty upon such factual predicates, a jury’s verdict is not unanimous unless its findings are unanimous.
¶7Here, we know that the death-penalty decision was unanimous, but we do not know upon what finding or findings it was based. This is because, as defendant says, the verdict form is fatally ambiguous. The form, submitted by the trial court and returned without change by the jury, read as follows:
We, the jury, on the issue joined, having found the defendant guilty of the willful, deliberate and premeditated killing of Ofelia Quintero in the commission of robbery while armed with a deadly weapon and that after consideration of his prior history that there is a probability that he would commit criminal acts of violence that would constitute a continuing serious threat to society or his conduct in committing the offense is outrageously or wantonly vile, horrible or inhuman in that it involved depravity of mind or aggravated battery to the victim, and having considered the evidence in mitigation of the offense, unanimously fix his punishment at death [emphasis added].
¶8The trial court did not instruct the jurors to delete any finding or part or parts of any finding upon which they failed to reach unanimous agreement. Yet, the majority conducts its dispropor*154tionality analysis upon the theory that all the jurors agreed that the Commonwealth had established both the dangerousness predicate and the vileness predicate. But this is no more than a theory. The jury’s verdict stated the two death penalty predicates in the alternative. No one can tell whether the jury found both predicates or only one, and if only one, which one. Indeed, it is possible that some jurors found only the dangerousness predicate and other jurors only the vileness predicate, while other jurors found both. Even if a plurality or a majority of the jurors agreed upon one or both of the death-penalty predicates, the verdict is not constitutionally sufficient.
¶9The possibility of diversity in the verdict is heightened by the fact that the jurors were told in a separate instruction that they could impose the death penalty if the Commonwealth proved “at least one” of the statutory predicates. An individual juror could have interpreted that instruction to mean that he was free to vote for the death penalty if he found only one of the predicates, even if all the other jurors disagreed with his finding.
¶10For purposes of the disproportionality analysis, “similar cases” are those in which the penalties were based upon the same predicate (or predicates) as that underlying the penalty under review. Evans v. Commonwealth, 222 Va. 766, 778, 284 S.E.2d 816, 822-23 (1981) (dangerousness only). See also Fitzgerald v. Commonwealth, supra (vileness only); Clanton v. Commonwealth, 223 Va. 41, 286 S.E.2d 172 (1982) (dangerousness and vileness). Because we cannot determine upon what finding or findings defendant’s death penalty was predicated, we cannot identify “similar cases” for purposes of comparison. Hence, we are unable to determine whether his penalty is excessive or disproportionate. Under such circumstances, we have no authority to remand the case for a new penalty trial; our only option is to “[c]ommute the sentence of death to imprisonment for life.” Code § 17-110.1(D)(2). See Wm. *155Patterson v. Commonwealth, 222 Va. 653, 660, 283 S.E.2d 212, 216 (1981).
¶11I am in accord with the view that the evidence is sufficient to support a finding of either death-penalty predicate, but I cannot agree that the record shows that the jury reached unanimous agreement on either, much less on both. In my view, commutation is a constitutional and statutory imperative.
¶12STEPHENSON, J., joins in this concurring and dissenting opinion.
¶13 I am aware that we have rejected challenges to the verdict form in two recent appeals. But there was no room for ambiguity in either case. In Turner v. Commonwealth, 221 Va. 513, 273 S.E.2d 36 (1980), the appendix showed that the verdict form submitted by the trial court instructed the jurors to “[cjross out any paragraph, word or phrase which you do not find beyond a reasonable doubt.” See Virginia Model Jury Instructions 1-437 which contains the same language. And in James Dyral Briley v. Commonwealth, 221 Va. 563, 577, 273 S.E.2d 57, 66 (1980), “[e]ach member of the jury was polled individually and each responded affirmatively that both aggravating circumstances were present.”