@stonedgnome I would not think of it as my child committing murder, if they were only 6. I would think of it as they really didn't understand what they were doing, and personally, I would probably blame myself (for being in the other room, for example, even though that's going to happen to all parents at some point). (And IMO this is also why you see even parents/relatives of violent teenagers defending them. Because it's still their child, and they look for reasons to explain why the child did what they did.)
And I think you would not want to "lose" another child, even psychologically, so you would have to blame something else, such as "an accident," etc.