Boston September 14, 2017 11:30 pm Training for Mass Casualty Events at Camp Edwards Hundreds of first responders took part in one of the biggest mass casualty drills in state history. US & World Videos 2:31 Billerica police sergeant killed in crash honored at funeral 2:05 MIT monitors pair of opposing protests on campus 2:39 Bruins try not to ‘dwell on the past' ahead of Game 7 against Toronto Maple Leafs 3:46 How first responders described Karen Read's actions at the scene of John' O'Keefe's death 5:08 Karen Read trial jurors visit scene of John O'Keefe's death