On Monday evening in Houston, a dozen armed men broke into the home of Dennis Tuttle and Rhogena Nicholas, a middle-aged couple who had lived in the house at 7815 Harding Street for at least two decades. The first man through the door, who was armed with a shotgun, used it to kill one of the couple's dogs. Tuttle responded to the home invasion by grabbing a revolver and shooting the man with the shotgun, who collapsed on a sofa in the living room. As Nicholas tried to disarm the intruder, his accomplices shot her. Tuttle returned fire, and by...