What is the test for a jury to convict a defendant of second degree murder of unintentional killing with malice?

We agree that the trial court erred. A court must "instruct, sua sponte, on all theories of a lesser included offense which find substantial support in the evidence." (People v. Breverman (1998) 19 Cal.4th 142, 162, 77 Cal.Rptr.2d 870, 960 P.2d 1094.) Appellant contends that the evidence permitted an inference that the murders were not committed with premeditation but were committed in a panic when the victims put up unanticipated resistance and made noise. Murder was defined as "the unlawful killing of a human being with malice aforethought or the unlawful killing of a human being which occurs during the commission or attempt to commit a felony inherently dangerous to human life." The court instructed that the necessary mental states for first degree murder were premeditation, deliberation, and malice aforethought, and that in second degree murder "the necessary mental state is malice aforethought." In further defining second

[23 Cal.4th 586]

degree murder, however, the court instructed only: "Murder of the second degree is also the unlawful killing of a human being with malice aforethought when there is manifested an intention unlawfully to kill a human being but the evidence is insufficient to establish deliberation and premeditation." The court did not instruct the jury that second degree murder included unintentional killing with malice, and did not define implied malice.

[23 Cal.4th 586]