In pictures Boston bombing: police involved in shoot-out in Watertown A tense night of police activity just days after the Boston Marathon bombings has caused police to converge on a neighborhood outside Boston where they say there were explosives. The chaos in Watertown, about 10 miles (16 kilometers) west of Boston, occurred just hours after a Massachusetts Institute of Technology police officer was shot and killed on campus. It was unclear if the outbursts of violence were related. No arrests had been made in the officer's fatal shooting, and a manhunt was on for the shooter.Picture: Mario Tama/Getty Images