A police officer for the Massachusetts Institute of Technology (MIT) has been shot and killed at the campus outside Boston, authorities said early Friday. As the manhunt began for the shooter, police reportedly became involved in a chase with several suspects in which explosives went off and gunshots rang out.
Live news reports said police officers were dealing with explosives left on the ground after the chase in the Watertown area, just west of Cambridge where MIT is located and eight miles to the west of central Boston. Police were told to switch off mobile phones and other electronic devices for fear of setting off explosives.
Police converged on a Watertown neighbourhood where there were reports of explosives being detonated and police also told reporters to turn off their phones.
Dozens of officers and National Guard members arrived and television outlets report that gunfire and explosions had been heard. A helicopter was circling overhead.