A 14 year old eighth grader shot and killed an openly gay 15 year old classmate. Evidence showed Larry King had worn high heels and makeup to school, and that he often teased Brandon McInerney. McInerney brought a gun to school and shot King twice in the back of the head while they were in English class. He had told a friend the day before that he planned to bring a gun to school the next day.
McInerney was tried as an adult. The prosecution theory was that this was a first-degree murder, planned, contemplated and discussed in advance, and carried out with conscious intent to kill. The defense presented the case of an overwhelmed child who felt sexually harassed by the gay teen's unwanted attention and snapped. There was no dispute that McInerney pulled the trigger. The only question was his state of mind.
Murder in California is a killing with malice aforethought. Malice is found when the defendant intended to kill. If a murder is committed with premeditation and deliberation, it is first-degree murder. (There are other ways of elevating a murder from second to first degree, but they aren't relevant here.)
A murder can be reduced to voluntary manslaughter if the person acted in the heat of passion. A killing in the heat of passion requires 1) that the defendant was provoked, 2) that the provocation caused the defendant to act rashly and under the influence of intense emotion that obscured his judgment and reasoning, and 3) the provocation would have caused the average person to act rashly. In other words, the defendant was so provoked by what the victim did, and reasonably so, that he acted out of intense emotion rather than deliberate judgment.
The jury was unable to make a decision in this case, and a mistrial was declared. McInerney will have to be tried again. The jury simply could not decide whether McInerney acted deliberately or in the heat of passion.
UPDATE 11/21/11: McInerney pled guilty to second-degree murder and voluntary manslaughter, accepting a sentence of 21 years in prison, and avoiding a second trial.
For more about the differences between murder and manslaughter, check out the Resources section.