What is the mitigating factor distinguishing the "heat of passion" form of voluntary manslaughter from the murder?

The mitigating factor distinguishing the "heat of passion" form of voluntary manslaughter from murder is provocation. (People v. Avila (2009) 46 Cal.4th 680, 705.) "Provocation has this effect because of the words of section 192 itself, which specify that

Page 52

an unlawful killing that lacks malice because committed 'upon a sudden quarrel or heat of passion' is voluntary manslaughter." (People v. Rios (2000) 23 Cal.4th 450, 461.) "The provocation which incites the defendant to homicidal conduct in the heat of passion must be caused by the victim [citation], or be conduct reasonably believed by the defendant to have been engaged in by the victim. [Citations.] The provocative conduct by the victim may be physical or verbal, but the conduct must be sufficiently provocative that it would cause an ordinary person of average disposition to act rashly or without due deliberation and reflection. [Citations.] 'Heat of passion arises when "at the time of the killing, the reason of the accused was obscured or disturbed by passion to such an extent as would cause the ordinarily reasonable person of average disposition to act rashly and without deliberation and reflection, and from such passion rather than from judgment." ' [Citation.]" (People v. Lee (1999) 20 Cal.4th 47, 59.)