What is the test for aiding and abetting in a murder case?

mens reaknowledge of the direct perpetrator's unlawful intent and an intent to assist in achieving those unlawful ends, and (c) the aider and abettor's actus reusconduct by the aider and abettor that in fact assists the achievement of the crime." (People v. Perez (2005) 35 Cal.4th 1219, 1225.) "[N]either presence at the scene of a crime nor knowledge of, but failure to prevent it, is sufficient to establish aiding and abetting its commission. [Citations.] However, '[a]mong the factors which may be considered in making the determination of aiding and abetting are: presence at the scene of the crime, companionship, and conduct before and after the offense.' " (People v. Campbell (1994) 25 Cal.App.4th 402, 409.) Where, as here, "the charged offense and the intended offense . . . are the same, i.e., when guilt does not depend on the natural and probable consequences doctrine . . . the aider and abettor must know and share the murderous intent of the actual perpetrator." (People v. McCoy (2001) 25 Cal.4th 1111, 1118.)

2. Analysis