NONGOMA, South Africa — The hit man struck simply after midnight. His bullet shattered a window, punched by way of a 4-year-old boy and slammed into the physique of his grandmother as she slept beside him, a member of the family recounted in an interview. The sufferer, Ntombenhle Mchunu, was a soft-spoken 75-year-old city councilor. That place had made her a goal.