My three year old will hit when he's playing, without really understanding that it hurts people. I can believe that the 3yo didn't realize he was hurting her, and I can certainly say he had no concept of killing.
I disagree. He can have no serious concept of what death is, but I have no doubt whatsoever that he did it on purpose, and that he was trying to kill her. (Maybe he learned the idea from TV, or from one of Morticia's boyfriends.)
Same here. My three year old will hit with whatever she has at hand, including books and juice cups. If she had a steak knife, I suppose she might hit with that. Impulse control is not that great with three year olds...