We don’t know for sure that she killed her brother intentionally.
One other article stated that Amy and her FATHER were having an argument. One could conjecture that she took the shotgun, went to her room and started blowing holes in the wall in some violent rage. One of the shots could have gone through the wall and hit her brother.
I do not know her age at the time, so possibly that was a factor. It would have been involuntary manslaughter, instead of murder, if that scenario is true.
The problem is that there seem to be so many ‘contradictory’ explanations from the Father, Mother, and Police, that it is very hard to tell what really happened.
One thing for sure. The woman is a real nutcase.
How do you accidentally fire a pump action shot gun 3 times on two different floors of your house?