@krazy kaju,
This is a classic Leo Katz example of criminal intention.
The question is;
"Diane, Kate, and Benjamin are walking together in the Sahara desert. Kate and Diane knows that Benjamin has been cheating on them, so they plan to kill him. Before leaving Asyut, Diane poisioned Ben's water canister. During the trip, Kate, without knowing what Diane did, punctured Ben's canister and the poison drained. And then Ben died of thirst. (Diane and Kate later became lesbians.) Anyhoo, who killed Ben?"
Diana and Kate possess what is known as
malice aforethought. They intentionally, before the crime was committed, considered the crime and carried through with actions that were intended to cause Benjamin harm. Like the question says? "they plan to kill him (Benjamin)." But there is problem with premeditation at this point. Guilty thoughts do not equal guilty crimes, so at this point, there is no reason to suppose that either Kate or Diane are guilty.
But the question is whether Diane or Kate or both are responsible for Benjamin's death.
Diane poisons Benjamins water first. But Kate independently puts a hole in Benjamin's canteen. By all superficial accounts, Kate is clearly responsible because it was that final causation that killed Benjamin, as he died from thirst and not poison. But Kate is not the only person responsible. The intention to kill Benjamin was clear, but also the attempt. The
law of attempts basically states that a failed crime can still be a crime. Though the poisoned water never touched Benjamin's lips, the intent of Diane and Kate makes them accomplices in a criminal act, and the attempt to kill was clearly there. I think the main thing to think about is the primary legal principle in the matter, which is an act (unless interrupted) constitutes a crime? is a criminal attempt. However, an act, which even if completed, wouldn't be crime, is not.
So basically, Both Kate and Diane are guilty under malice aforethought, intent, and criminal attempt, but under precedence of the law and a very hazy view of the duty of care, Diane could theoretically walk away.
Also, I second krazy kaju? the hot lesbian defense is a tough defense to beat in a court of law. And although I am joking to a point? I am partially not. You would be surprised what something like that could do to sway a case. Look at Deborah Lefave.