What is an aider and abettor of a murder charge?

knowledge of the criminal purpose of the perpetrator and with an intent or purpose either of committing, or of encouraging or facilitating commission of, the offense.' [Citation.] When the offense charged is a specific intent crime, the accomplice must 'share the specific intent of the perpetrator'; this occurs when the accomplice 'knows the full extent of the perpetrator's criminal purpose and gives aid or encouragement with the intent or purpose of facilitating the perpetrator's commission of the crime.' [Citation.] Thus, we held, an aider and abettor is a person who, 'acting with (1) knowledge of the unlawful purpose of the perpetrator; and (2) the intent or purpose of committing, encouraging, or facilitating the commission of the offense, (3) by act or advice aids, promotes, encourages or instigates, the commission of the crime.' [Citation.]" (People v. Prettyman (1996) 14 Cal.4th 248, 259, quoting People v. Beeman (1984) 35 Cal.3d 547.)

Murder is the killing of a human being with malice aforethought. ( 187 subd. (a).) Malice is express when "there is manifested a deliberate intention unlawfully to take away the life of a fellow creature." ( 188) "[U]nlawful 'intent to kill' is the functional equivalent of express malice. [Citation.]" (People v. Swain (1996) 12 Cal.4th 593, 601.) Express malice can be inferred from the act itself together with its surrounding circumstances. (People v. Lewis (2001) 25 Cal.4th 610, 643.)