© MattRourke/APPolice officers walk near a crime scene Friday, April 19, 2013, in Watertown, Mass. A tense night of police activity that left a university officer dead on campus just days after the Boston Marathon bombings and amid a hunt for two suspects caused officers to converge on a neighborhood outside Boston, where residents heard gunfire and explosions.
All public transportation was shut down in the greater Boston area Friday morning, for reasons of public safety, officials said. Residents of Watertown and several surrounding suburbs were asked to stay inside, and businesses were instructed not to open.
"This situation is grave. We are here to protect public safety," Police Commissioner Ed Davis said. "We believe these are the same individuals that were responsible for the bombings Monday at the Boston Marathon" and the killing and wounding of the police officers overnight.
The mayhem began about 10:30 p.m. when an Massachusetts Institute of Technology campus police officer responded to a disturbance. That officer was found fatally wounded inside his vehicle on the campus in Cambridge, according to the Middlesex District Attorney's office.
The shooting launched a massive police response. A short time later authorities received reports of an armed carjacking by two males nearby in Cambridge. Police immediately began a search for a Mercedes SUV that had beentaken at gunpoint by the two males and was later spotted in neighboring Watertown, the district attorney's office said.
Watertown police officers located the vehicle and after stopping it, exchanged gunfire with two men in a residential neighborhood. During the firefight, authorities said, multiple explosive devices were thrown from the vehicle and some exploded, which led to panic and concern in the town.
A transit police officer was critically wounded in the firefight, authorities said.
Police fatally shot one suspect during the firefight, the district attorney's office said. He was taken to Beth Israel-Deaconness Hospital, where he was pronounced dead, doctors there said.
The man, whom authorities later identified as the suspect pictured in a black baseball cap in photos released Thursday evening, had been shot multiple times in the torso and also sustained injuries from sort of explosives, doctors at the hospital said. He was in cardiac arrest when he arrived at the hospital, and could not be revived.
A second man fled the vehicle on foot, which prompted a massive search by authorities. They created a 20-block perimeter in a section of Watertown and advised residents to lock their doors and only answer to uniformed police officers.
"We have an active search going on by tactical teams. He's considered armed and dangerous," Col. Timothy P. Alven, said at a televised early morning news conference. Officials said police were conducting a door-to-door search.
Investigators believe the man who is at large is suspect No. 2 in the photos, which were culled from surveillance footage shortly before Monday's attack. He was pictured wearing a white hat on Monday.
At the news conference, officials released a surveillance photo from a convenience store in Cambridge taken before the fatal shooting at MIT. That photo showed a man police also believe is suspect No. 2. He was wearing a gray hooded sweatshirt late Thursday night.
Law enforcement officials said they are shutting down the transportation system and are instructing residents to stay indoors because they believe suspect No. 2 may be strapped with explosives.
Bomb squad technicians worked to render several devices safe that had been thrown at police during their confrontation with the suspects after the stolen SUV was stopped, Alven said.
until the 2nd one is dirt napping too. Remember, dead men don't talk.