A gunman wearing military gear and livestreaming with a helmet camera opened fire with a rifle at a Buffalo, New York, supermarket in what authorities called “racially motived violent extremism,” killing 10 people and wounding three others Saturday before he was arrested, authorities said. Police officials said the gunman, who also wore body armor in addition to military-style clothing, pulled up Saturday afternoon and opened fire with a rifle at a Tops Friendly Market, adding the shooting was streamed via a camera affixed to the helmet. Gramaglia said the gunman shot four people outside the store, and three of them died.