The majority opinion in People v. Smith (2014) 60 Cal. 4th 603 concluded that the requirement of juror unanimity as to all essential elements of the charge does not apply to commission of the nontarget offense alleged under the natural and probable consequences doctrine:
The prosecution theory was that Littleton was the killer. But exactly who shot and killed the two victims was not entirely clear….Naturally, in order to return a guilty verdict, the jury must agree unanimously that each element of the charged crime has been proved, but the factors that establish aiding and abetting liability are not included as elements of the crime of murder. … “Once the discrete event is identified, for example, the killing of a particular human being, the theory each individual juror uses to conclude the defendant is criminally responsible need not be the same and, indeed, may be contradictory.” [Citation.] It suffices if the jury unanimously agrees that the prosecution has proven beyond a reasonable doubt every element necessary to establish guilt of a discrete crime. (Id. at pp 617-18.)
However, as Justice Lui persuasively argued in his concurring opinion, commission of the nontarget offense is an essential element of natural and probable consequence liability:
Today’s extension of the Santamaria rule is problematic because an essential element of proving that a defendant committed murder under a natural and probable consequences theory is valid proof that one (or more) of the defendant’s confederates committed murder. (See People v. Prettyman (1996) 14 Cal.4th 248, 267 [natural and probable consequences liability requires proof that “the defendant’s confederate committed an offense other than the target crime(s)” (italics omitted)].) Our case law has always held—and today’s opinion does not dispute—that independent and satisfactory proof of the nontarget offense is itself a necessary element of proving a defendant’s vicarious liability for that offense under a natural and probable consequences theory. A finding by six jurors that Littleton (and no one else) committed murder, together with a finding by six other jurors that Moody (and no one else) committed murder, does not add up to a valid finding that anyone committed the nontarget offense of murder in this case. We have never said that murder can be proven that way, and we should not adopt a special rule here. It is no answer to say that “[t]he jury certainly had to find that someone committed murder.” (Maj. opn., ante, 180 Cal.Rptr.3d at p. 113, 337 P.3d at p. 1170.) To say the jury found that “someone committed murder” is a conclusory play on words. There is no finding of “murder” under the law simply because each of twelve jurors believes “someone” killed with malice. Even if Smith’s liability for murder does not depend on whether Littleton or Moody (or anyone else) would be convicted of murder if tried in a separate proceeding (cf. People v. Wilkins (1994) 26 Cal.App.4th 1089, 1093–1096 it is essential that the jury in this proceeding find valid proof of the nontarget offense of murder. As a point of contrast, it would not matter whether the jury could determine who killed each victim if the jury had found that all possible shooters acted with malice aforethought toward Hunt and McCarthy. In that scenario, each possible shooter would have been either a perpetrator or an aider and abettor of the murders and, as such, would have been liable for murder, no matter who actually shot each victim. But the jury instructions in this case did not require any such finding as to all possible shooters, and the record does not compel such a finding beyond a reasonable doubt. In sum, a finding by each member of the jury that someone within the group of possible shooters killed the victims with malice—without any agreement on the shooter’s identity or a unanimous finding that all possible shooters acted with malice—is not valid proof that anyone committed the nontarget offense of murder. Without such proof, an essential element of Smith’s liability for murder under a natural and probable consequences theory is missing.
People v. Smith (2014) 60 Cal. 4th 603, 622-23, 337 P.3d 1159, 1172
See also, Mendez, California Evidence Code—Federal Rules of Evidence (7th Ed. 2019) Section III(IX) [“…jury unanimity should … be required in finding preliminary facts that constitute elements of the offense charged.”].
Strategy Note: Until this question is definitively resolved in federal court counsel may wish to request a unanimity instruction in such situations under clearly established USSC precedent which mandates that the prosecution prove every essential element of the charge. (Apprendi v. New Jersey (2000) 530 U.S. 46; In re Winship (1970) 397 U.S. 358.) “Failure to submit to the jury the essential elements of the crime is ‘fundamental’ error.” (Screws v. United States (1945) 325 U.S. 91, 107.)