UPDATE 10:00 a.m. ET: A third suspect, described in news reports as an accomplice of the Tsarnaev brothers, is believed to be on board a New-York-bound Amtrak train that has been halted in East Norwalk, Conn., and authorities have surrounded the train.
Massachusetts Gov. Deval Patrick told residents of Boston and nearby suburbs to stay indoors as a massive manhunt continues for the surviving suspect wanted in connection with the Boston Marathon bombings. Police identified him as Dzhokar Tsarnaev, 19, of Cambridge, Mass.
The dead man, identified as his Tsarnaev's older brother Tamerlan, 26, was killed in a confrontation with law enforcement officers last night after an MIT security officer was shot dead while sitting in his vehicle and a 7-Eleven store was robbed. Media reports say that the brothers are linked to both incidents.
The FBI broadcast the images of both men around the world yesterday after reviewing countless hours of video from surveillance cameras and cellphone videos submitted by people who were near the bombings. Within hours the violence erupted in Boston.
Swarms of law enforcement officials are conducting a door-to-door search of the area, but the suspect is still at large. Two people have reportedly been taken into custody in Watertown without being arrested.
"Don't open the door for anyone except identified law enforcement officers" Patrick told area residents in a news conference. He all residents of Boston and the suburbs of Watertown, Waltham, Newton, Belmont, Cambridge, to "shelter in place."
The Boston-area transit system has been shut down, forcing hundreds of thousands of commuters to return home. Colleges and schools across the area are closed. Boston-bound Amtrak trains were stopped in Providence. Authorities ordered all taxi services to stop. The Federal Aviation Administration set up a no-fly zone over Watertown area.