What is the test for a jury to convict a defendant of murder?

The facts and circumstances of People v. McDonald, supra, illustrate this rule. There the defendant was found guilty of murder. In addition, a special circumstance allegation, i.e., the murder occurred while the defendant was [50 Cal.App.4th 929] engaged in the commission of a robbery, was found true by the jury. The defendant was, however, acquitted of the robbery that formed the basis of the special circumstance allegation. As is the case here, the jury verdict form did not specify the degree of murder. ²