The situation was fluid, and the latest development came in the city’s Watertown section after a chaotic night of mayhem that included the murder of a Massachusetts Institute of Technology police officer and a shootout with police, authorities said early Friday.
Police believe the two suspects from Monday’s terror attack are brothers, possibly from Chechnya, according to sources who spoke to Fox News. The man on the loose was identified as Dzhokhar A. Tsarnaev, 19, of Cambridge, Mass. They are believed to have been here for ‘several years,’ sources said.
Schools are closed, train and bus service is suspended and police were telling residents of neighborhoods including Cambridge, Waltham, Watertown, Newton, Arlington and Belmont to stay indoors. Police have formed a wide perimeter and believe the suspect is on foot, armed and dangerous, inside.
“Suspect No. One is dead, Suspect Two is on the run,” Massachusetts Gov. Deval Patrick said at a Friday morning press conference. “There is a massive manhunt underway.”
The dead suspect, Tamerlan Tsarnaev, was shot multiple times in a gunfight with police Thursday night and pronounced dead at a hospital.
The suspects apparently surfaced just hours after the FBI released their imaged late Thursday afternoon, shooting the police officer, robbing a convenience store, carjacking a man who later escaped and engaging in a wild shootout with Boston police, in which they hurled explosives from their stolen car.
Boston Police Commissioner Ed Davis said on Twitter that one of the two suspects was killed and that the at-large suspect, labeled by the FBI as “suspect two” in the marathon bombing, was “armed and dangerous.”
Authorities urged residents in Watertown, Newton, Waltham, Belmont, Cambridge and the Allston-Brighton neighborhoods of Boston to stay indoors. All mass transit was shut down.
“We believe this to be a terrorist,” Davis said in a press conference. “We believe this to be a man who’s come here to kill people. We need to get him in custody.”
The Middlesex district attorney said the two men are suspected of killing the MIT police officer on campus late Thursday, then stealing a car at gunpoint and later releasing its driver unharmed. Hours earlier, police had released photos of the marathon bombing suspects and asked for the public’s help finding them.
The suspects threw explosives from the car as police followed it into Watertown, according to the district attorney’s news release. The suspects and police exchanged gunfire, and one of the suspects was critically injured and later died while the other escaped.
During the pursuit, a MBTA transit police officer was seriously injured and transported to the hospital, the news release states. He was identified as Richard H. Donahue Jr., 33, and was being treated at Mt. Auburn Hospital..
Hours earlier, police had released photos of the marathon bombing suspects and asked for the public’s help finding them. A new photo of the suspect on the loose was released later showing him in a grey hoodie sweatshirt. It was taken at a 7-Eleven in Cambridge, just across the Charles River from Boston.
A federal law enforcement official told Fox News they are looking into whether the bombing suspects may have been from overseas and had overseas military training.
Dozens of officers and National Guard members descended on Watertown shortly after the shooting outside a building on MIT’s campus in Cambridge, according to the Associated Press.
Authorities were calling for somebody to get on the ground and put their hands up and a loud thud was heard after someone shouted “fire in the hole,” the news agency reported.
Witnesses told The Associated Press they heard multiple gunshots and explosions at about 1 a.m. Friday. Dozens of police officers and FBI agents were in the neighborhood and a helicopter circled overhead.
State police spokesman David Procopio told news agency, “The incident in Watertown did involve what we believe to be explosive devices possibly, potentially, being used against the police officers.”
Doctors at Beth Israel Deaconess Medical Center in Boston where a suspect in the marathon bombings was taken and later died said they treated a man with a possible blast injury and multiple gunshot wounds. They wouldn’t say if the patient they treated, who came in with police, was the suspect in the black hat from marathon surveillance footage.
Earlier Friday, Cambridge police and the Middlesex District Attorney’s office said the MIT officer was responding to a report of a disturbance when he was shot multiple times late Thursday. He later died at a hospital. His name was not immediately released.
Procopio said the shooting took place about 10:30 p.m. outside an MIT building. The area was cordoned off and surrounded by responding law enforcement agencies, according to a posting on the university’s website.
The shooting came little more than three days after the twin bombings on the Boston Marathon that killed three people, wounded more than 180 others and led to an increase in security across the city.
Fox News’ Jennifer Griffin, Jana Winter, Mike Tobin, Mike Levine, Griff Jenkins and The Associated Press contributed to this report.