I hadn't heard this story. Wow, just wow.
Read the details. While I agree an 8 year old isn't really 'responsible', look at the details here. It was no 'accidental shooting'. It was a single-shot 22, the 8 year old had to load one round at a time, fire it, then reload. He killed his father, it does not say how many shots that took. But then the 8 year old called down the other man (he rented a room at the house) and shot and killed him (again not told how many shots that took).
The only possible motive is that the boy was spanked because he did not bring his school homework home. Nothing there says he was an abusive father.
I've never thought a child this young was really due corporal punishment, but this is a first. As others have said, we're going to hear about this boy again. He's going to kill again, the only questions are who and when. I do not see a reason to give him that opportunity. He should be put down like a rabid dog, and it should have happened 10 years ago. This is so sad.