maybe the 12 deaths were intruders or home invaders and died by the gun/homeowner and the 5 deaths were gunless/homeowner at the hands of intruders. That would be one way of explaining it.
Oh, logic and reason again, you racist!/sarc
I don't think they're talking about intruders, but the person who lives in the same house with a gunowner, ie, victim is wife, children, partner, roommate, mother-in-law.