The police on Friday captured a 19-year-old ethnic Chechen with his elder brother as a second suspect of the Boston marathon bombings after an intense day-long manhunt on Friday that closed down the city and turned a working-class suburb into a virtual armed camp.
A short time later, police received reports of a carjacking by two men who kept their victim inside the car for about half an hour, the statement said.
Police pursued that car to Watertown, where explosives were thrown from the car at police and gunfire was exchanged, the statement said.
"During the exchange of the gunfire, we believe that one of the suspects was struck and ultimately taken into custody. A second suspect was able to flee from that car and there is an active search going on at this point in time," Colonel Timothy Alben, superintendent of the Massachusetts State Police, told a news conference.
Police killed one suspect in the Boston Marathon bombing during a shootout and were engaged in a house-to-house search for the other on Friday in the Boston suburb of Watertown.
"What we are looking for right now is a suspect consistent with suspect No. 2, the white-capped individual who was involved in Monday's bombing of the Boston Marathon," Alben said. Here's the coverage of the police manhunt for the two suspects:
8.20 pm: The hunt for the second suspected marathon bomber continues as heavy police force is now deployed. Media personnel asked to get back and stay down.
6.15 pm: The governor of Massachusetts has asked all the residents to stay indoors. All colleges and schools to remain closed today.6:00 pm: Boston police tweeted suspect identified as 19 year-old Dzhokhar Tsarnaev of Cambridge. Suspect considered armed & dangerous.
5:50 pm: All taxi services has been halted until further further notice.
5:40 pm: Colonel Timothy Alan from the state police told the news conference that authorities need more time to capture the suspect.
5:35 pm: Boston authorities have extended the shelter in place recommendation to the wider city of Boston. That means a wide-scale shutdown of the city. Businesses should shut and public transport will remain shut down.
5:30 pm: Surviving Boston bombing suspect named by US officials as Dzokhar Tsarnaev.
5:10 pm: Reuters now joins several other US media outlets in reporting that the two Boston suspects are Dzhokhar Tsarnaev and his brother Tamerlan Tsarnaev. Reuters cites a national security official.
4:50 pm: ABC News confirms surviving Boston marathon bomb suspect's name is Dzhokhar Tsarnaev.
4:40 pm: Police are engaged in a house-to-house search for a second man on Friday in the Boston suburb of Watertown after a bloody night of shooting and explosions in the city's streets.
4:30 pm: AP says the surviving bombing suspect is 19-year-old Dzhokhar A Tsarnaev.
4:20 pm: US network NBC News is now reporting that the two suspects are brothers - and has released their names, which have not yet been confirmed by police.
4:10 pm: AP sources: Boston bomb suspects from Russia region near Chechnya, lived in US at least 1 year.
4:00 pm: CNN reports officials claim that the one of the Marathon blast suspects had explosives on his body.
3:50 pm: Residents in Watertown, Newton, Waltham, Belmont, Cambridge and the Allston-Brighton neighbourhood in Boston are being asked to stay indoors and stay in their homes. Vehicle traffic is restricted and businesses in those areas are also being asked to not open until further notice.
3:40 pm: The sun is up and police and SWAT are going house to house looking for the remaining suspect and evacuating locals from their homes on the street that the suspects abandoned their stolen car.
3:30 pm: Undersecretary for Homeland Security Kurt Schwartz asks people in Watertown and surrounding suburbs not go to work today.
3:23 pm: The MBTA, which runs transport services in and around Greater Boston, has suspended all services at the request of police.
3:18 pm: Medics at Beth Israel Hospital in Boston: Hospital was notified at 01:10 local time that a patient was coming in with multiple injuries. He arrived at 01:20 - at that point he was in a "traumatic arrest" undergoing CPR. At 1:35 he was pronounced dead.
3:15 pm: Medics at Beth Israel Hospital in Boston: Hospital was notified at 01:10 local time that a patient was coming in with multiple injuries. He arrived at 01:20 - at that point he was in a "traumatic arrest" undergoing CPR. At 1:35 he was pronounced dead.
3:10 pm: Full statement from Massachusetts police on the dramatic night-time events.
3:00 pm: Police are searching house-to-house for the second suspect. Massachusetts State Police say via Twitter: "Police will be going door by door, street by street, in and around Watertown. Police will be clearly identified. It is a fluid situation."
2:50 pm: One Watertown resident, Kristian Tunzig, tells BBC News he heard successive gunshots close to his house earlier and then saw a black Mercedes sedan crash in front of the house. There was a 10 to 15 minute gunbattle and several explosion - before a huge explosion. He says he hid in a closet and came out later to discover a bullet lodged in his bed.
2:45 pm: While officials are urging residents to remain inside and call 911 if they see the suspect, there are also reports of some unexploded devices on the streets of Watertown following the earlier pursuit.
2:40 pm: "One suspect dead. One at large. Armed and dangerous. White hat suspect at large," Boston Police Commissioner Ed Davis tweeted.
2:34 pm: Police said they have shot dead one of the suspects in the Boston Marathon bombing and were searching for another who was at large in the Boston suburb of Watertown.
02.20 pm: The police say the search for the second suspect is on, who they say is "armed and dangerous".02.15 pm: The Boston police reveal one of the suspects of the Boston Marathon bombings, known as 'Black Hat' has been killed. The other suspect 'White Hat' is still on the run in the Watertown.
12:28 pm: A spokesperson for the Massachusetts State Police says two suspects are "accounted for" in Watertown. They say officials do not know how many there are in all. The spokesperson confirmed multiple explosive devices were used against police.
12:25 pm: Boston Police Department's official Twitter feed says "there is an active incident ongoing in Watertown. Residents in that area are advised to remain in their homes. More details when available."
12:20 pm: FBI spokesman Martin Feely tells CNN's Susan Candiotti: "We are engaged with our partners trying to determine if there is a connection."
12:15 pm: It was not clear if the police activity in Watertown was related to the shooting at MIT, or if either was connected to the bombing of the Boston marathon, which killed three people and wounded 176. Police officers with weapons drawn, and people wearing FBI and ATF jackets could be seen in the live video.
12:08 pm: Peter Jennings, 33, told Boston Globe he was sleeping just before 1 am in his home on Prentiss Street in Watertown when he was awakened by a huge boom. “It sounded like a stick of dynamite went off,” he said. “I looked out the window, and it was like nothing I’ve ever seen – blue light after blue light after blue light.”
12:05 pm: Boston Globe reports one suspect in Monday’s Boston Marathon bombings has been captured, according to an official with knowledge of the investigation. Another remains on the loose in Watertown after a firefight with police. Authorities have established a 20-block perimeter as they search for him.
12:01 pm: BBC's Lynsea Garrison writes as the investigation into who was behind the Boston bombings goes on, Muslim communities are braced for a backlash should the perpetrator share their faith. Read on
11:55 am: Investigators released pictures of two suspects in the Boston Marathon bombing, seeking the public's help in identifying two backpack-toting men photographed on the crowded sidewalk on Monday before bombs exploded near the finish line.
11:52 am: There has been no official comment on the police operation, and whether it is linked to the shooting at the MIT campus or the bombings at the Boston Marathon on Monday.
11:51 am: Television footage from the town, some 9km from Boston, showed one man lying spread out on the ground, holding out his arms, surrounded by police. Huffington Post reported police have another suspect in custody and they're waiting for a positive ID.
11:49 am: BBC quoted witnesses in nearby Watertown report hearing explosions and gunfire amid a massive police hunt for the gunman. There was also a carjacking in the MIT campus in Cambridge and Homeland security has been called in.
11:47 am: A suspect has been arrested after a police officer for the Massachusetts Institute of Technology was shot dead on Thursday night at the school's Cambridge campus near Boston.
11:45 am: A police officer was shot at in the Massachusetts Institute of Technology (MIT) campus Thursday night, authorities said.
11:40 am: MIT police were sweeping the campus early on Friday, according to a campus alert. Massachusetts State Police and Cambridge police said they were assisting in the investigation.
11:35 am: On Thursday, investigators released pictures and video of two suspects in the Boston Marathon bombing, enlisting the public's help in identifying two men wearing backpacks and baseball caps in the crowd minutes before bombs exploded near the finish line.
11:30 am: A 30-second video shows the men known only as Suspect 1 and Suspect 2 walking single file a few paces apart along Boylston Street in central Boston. One wears a dark baseball cap and sunglasses. The other has a white baseball cap turned backwards.