This photo depicts South Los Angeles resident Sandra Polanco breaking down at the sight of a homicide shrine near her home this weekend. "Again, again," she said. "These accursed streets." She did not know the victim. But Polanco lost her son, Giovanni Mancia, 16, to a homicide almost a year ago. As she spoke, she gripped a cellphone containing Giovanni's picture. The hand with which she held the phone was shaking. Seeing her reaction, her remaining son, Jesus, 6, put his arms around her.