I would raise the point that as was raised in the house, if the concern with murder be that someone's life is being ended one must note that many of these crimes could lead to the same result.
An example comes to mind from the movie Dirty Dozen where Charles Bronson explains that the reason he is locked up because he shot a man who panicked and ran off with all the spare ammunition in a fire fight.
In a combat situation, most all of these cause the death of one's comrades.
I am not exactly in a position to research this, but isn't it often the case that accessory is charged the same when it comes to murder in a criminal sense?
Ftr I don't even support the death penalty for murder, but small steps...