In Cool v. United States (1972) 409 U.S. 100, the defense relied heavily on the testimony of an accomplice, who admitted his own guilt and insisted that the defendant had no culpability. The trial court told the jury that the accomplice's testimony should be viewed with suspicion, but that it could be considered if the jury was " 'convinced it is true beyond a reasonable doubt.' " (Id. at p. 102.) The trial court further instructed the jury that the accomplice's testimony, if believed, could "support your verdict of guilty . . . ." (Id. at p. 103, fn. 4.) The United States Supreme Court found the accomplice instruction deficient in two respects. First, it "placed an improper burden on the defense" to prove that the accomplice's testimony was true beyond a reasonable doubt. (Cool, supra, 409 U.S. at p. 103.) Second, it was "fundamentally unfair in that it told the jury that it could convict solely on the basis of accomplice testimony without telling it that it could acquit on this basis." (Ibid., fn. 4.)