WASHINGTON (AP) — The son of an 86-year-old woman killed in the racist Buffalo mass shooting is calling on Congress to act against domestic terrorism. Garnell Whitfield, Jr., whose mother was the oldest of the 10 Buffalo victims, challenged senators at a hearing Tuesday. He told them: “What are you doing? You were elected to protect us.” The emotional testimony came against the backdrop of intensifying Senate negotiations on a gun safety bill. The proposals are gaining traction, but also raising concerns from Democrats and some advocacy groups who are pushing senators to do more, faster, to stem the tide of mass shootings across the nation.