Man and associate shot by 8 year old son

How does one get over an event like this ? A 29 year old man and his associate (39 years old) were both found shot to death at this home. Now this is a tragedy, but what makes it really sad is the fact that both of them were shot by the 8 year old son of the 29 year old man. The father had apparently wanted to be responsible about the use of guns by his son, and had looked to get the son some gun training. He was from a family of hunters and wanted to make sure that his son was comfortable about the use of guns, and had even consulted a Roman Catholic priest about whether it was right for the 8 year old son to get training, or should it wait for later ? Read this story. http://abclocal.go.com/kabc/story?section=news/national_world&id=6495641&rss=rss-kabc-article-6495641
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ST. JOHNS, Ariz. -- A man who police believe was shot and killed by his 8-year-old son had consulted a Roman Catholic priest about whether the boy should handle guns and had taught him how to use them, the clergyman said Saturday. The father, Vincent Romero, 29, was from a family of avid hunters and wanted to make sure the boy wasn't afraid of guns and knew how to handle them, said the Very Rev. John Paul Sauter of St. Johns Catholic Church. The boy's stepmother had suggested he have a BB gun, the priest said.
The boy, who faces two counts of premeditated murder, did not act on the spur of the moment, St. Johns Police Chief Roy Melnick said. Police are looking into whether he might have been abused. "I'm not accusing anybody of anything at this point," he said Saturday. "But we're certainly going to look at the abuse part of this. He's 8 years old. He just doesn't decide one day that he's going to shoot his father and shoot his father's friend for no reason. Something led up to this."
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This is a case that you wish never happens. How do you treat an 8 year old, a child who is not even mature, as a killer ? How does the police handle such a case, how does a judge handle such a case ? Experts have to wonder what could lead a small child to take the cold blooded action of murder ?