By 3 News online staff
A police officer has been shot dead at Boston's Massachusetts Institute of Technology (MIT).
An alert on the university's website says gunshots were reported at 10:48pm Thursday local time (2:48pm Friday NZ time) near Building 32 on the university's campus. It is referring to the situation as an "active shooter incident", and says everyone in the area should stay inside.
"The area is cordoned off. Please stay clear of [the] area until further notice," the website says.
The officer was responding to report of a disturbance Thursday night when he was shot multiple times, according to a statement from the Middlesex District Attorney's office and Cambridge police.
Please refresh the page to see the latest updates. Information which is struck out has been confirmed to be incorrect later on in the pursuit.
4:32PM: Police radio activity suggests two Middle Eastern men, both armed with firearms, are the prime suspects in the shooting. They have reportedly stolen a vehicle at gunpoint from a civilian.
4:49PM: Loud explosions have been heard while police attempt to apprehend the suspects, and shots have been fired. The suspects are believed to be in possession of grenades and possibly other explosives.
4:55PM: Police radio chatter says another officer has been shot.
5:00PM: One suspect is now believed to be on foot and fleeing through a residential area in the suburb of Watertown, around 10 kilometres from MIT. Plainclothes police have been ordered not to engage the suspect.
5:03PM: Police are setting up a three block cordon in the area. This will be expanded after the initial cordon is in place.
5:05PM: Police in the area have been ordered to turn off their cellphones to avoid accidentally setting off any explosive devices.
5:06PM: Two explosive devices have been confirmed, one at the scene of the shooting of the second officer.
Unconfirmed reports both suspects have been apprehended. One is in an ambulance en route to Beth Israel hospital, and another is currently being held at gunpoint.
5:23PM: Police are searching for a possible third suspect. FBI officers are on the scene.
5:25PM: Massachusetts State Police have called for canine units to assist them at the scene. EOD bots are being used to disarm unexploded devices.
5:27PM: The second suspect may not be in custody. Police have reported sighting pressure cooker bombs.
5:29PM: A Watertown resident around 600m from the scene of the second shooting has reported hearing someone in her backyard to police.
5:33PM: The second suspect is reported to be in custody. He has been ordered to remove his clothing.
5:41PM: Image of a suspect as he was apprehended (source: CNN)
6:06PM: The above man may not be a suspect, but is being held in custody.
6:15PM: Police are searching a house about 700m from the scene of the second shooting, after movement was detected inside - the house is supposed to be empty. Units are preparing to enter the property.
6:45PM: Reporters are being told to move away from the scene. A police officer told a reporter: "If you want to live, turn off your cell phone."
6:48PM: Police are looking for a white suspect in a grey hoodie with curly hair. Caution has been advised as the man may be carrying an explosive device or assault rifle.
6:54PM: Boston police have confirmed to media one of the suspects is a man they are looking for in relation to Monday's bombing of the Boston marathon. The FBI has not confirmed this. State police are investigating a "strong link" between the bombing and today's fatal shooting.
7:02PM: Police have confirmed one suspect is in custody, while another remains at large.
7:07PM: Boston police radio chatter has identified two suspects, one of which is a Brown University student who has been missing for more than a month after leaving behind his wallet and phone.
7:32PM: Pressure cooker bombs have been found in Watertown.
7:46PM: Police have established and reinforced a perimeter in Watertown and are suspending their search until daylight. "Give the advantage to us," says one officer. The sun is due to rise around 5:56am in Boston - current local time is 3:46am.
7:51PM: People are being advised to be careful getting into cars and not to let anyone into their homes unless they can be identified as a police officer.
8:00PM: Motion sensors have been tripped at a building in Watertown. It is believed the suspect may have locked himself inside.
8:08PM: The earlier arrested man has been questioned by police three times. He remains in custody.
8:14PM: The Boston district attorney has announced one suspect was critically injured during the earlier police pursuit and has died. Police have released a new image of the second suspect, taken from security camera footage today:
8:22PM: Residents of East Watertown have been told to stay in their homes for the next few hours and are again advised to only open their doors to people they can confirm are police officers.
8:23PM: Boston police commissioner Ed Davis says "[we] believe this to be a terrorist, believe this to be a man who has come here to kill people."
8:42PM: A suspicious package on the MIT campus has been declared to pose no threat.
9:08PM: Police activity has quietened down. Sunrise will occur in around 50 minutes. An ambulance is currently en route to provide assistance to three injured officers, though the cause of their injuries is unclear. Boston residents are being reminded to stay indoors, and consider taking the day off work.
9:15PM: The second officer who was shot remains in a critical condition in hospital.
9:16PM: SWAT officers are searching neighbourhoods in pairs and reminding residents to remain indoors. The FBI has announced a press conference.
9:22PM: MIT has cancelled all classes for Friday.
9:24PM: Beth Israel hospital, the same hospital which treated most victims of Monday's bombing, is holding a press conference. A spokesman says the first suspect was brought to the hospital by police. He went into traumatic arrest. Attempts were made to revive him for around 15 minutes before he was confirmed to be dead.
9:28PM: The hospital says it has not confirmed the man's identity and will not release information about him other than to confirm it is an adult male. The suspect was shot several times and possibly suffered trauma from an explosive blast. "There were signs of more than just gun shot wounds" says a doctor who worked on the suspect.
9:32PM: Beth Israel's Doctor David Schonfeld said that he was at his Watertown home when he heard gun fire outside. He knew something was going on and he "knew or felt" that it was related to the events earlier in the week. He rushed to the Emergency Dep and arrived before the suspect got there. "You give the best care to every patient that comes to you no matter who they are," he says.
9:45PM: Dawn is starting to break and officers are beginning to search the area with bomb-sniffing dogs.
9:47PM: All public transport has been suspended in Boston. Residents in Watertown, Newton, Waltham, Belmont, Cambridge and Alston-Brightonare being advised to remain at home and schools have been closed. No vehicles will be allowed in or out of Watertown.
9:53PM: The FBI is trying to track the suspect inside the police cordon. View photos of the search.
9:56PM: Police are worried the second suspect may have explosives. They are warning the public "even if you are not near him you could be in danger".
10:02PM: FBI officers have searched a house on Dexter Avenue. They have left without anybody in custody.
10:12PM: "It's scary to think of your home as a war zone," says a local resident. More than 9000 law enforcement personnel are now believed to be in the greater Boston area.
10:17PM: Police have been heard yelling they have somebody in custody. This is not yet confirmed.
10:21PM: Officers have been heard yelling "GOT HIM". There is no official confirmation it is suspect number two. Officers are not retreating from the area.
10:24PM: Police officers have arrested three men, after pulling over a taxi. Two men are described as Middle Eastern, and one is a white male. Boston PD unit DA81 has called in the arrest. Police and local media are being cautious about the arrest after the earlier wrongful arrest. Unit DA81 confirmed one of the men was suspect two over the police scanner.
10:34PM: Buses are being used to transport people from the area out of their homes while police continue to search the area in case the arrested suspects are not related to the attack. Police have been told to continue their search.
10:46PM: The Associated Press is reporting the two suspects are Russian and have lived in the United States for at least one year and have US residency. They are said to be 19 and 20 years old. The AP claims the pair are brothers.
10:58PM: A reporter on the scene of the taxi arrest has seen two men being taken away in hand cuffs. A suspicious package is being investigated.
11:35PM: FBI agents have converged on an address believed to have been shared by the two men.
11:55PM: A woman has been arrested. The Boston Globe is reporting she is the girlfriend of the first suspect.
12:06AM: Police officer Timothy Alban says "we need more time" to find suspect. "It may take hours to do this".
All of Boston is instructed to stay indoors. Within the last half hour police have received more information and therefore the whole of the city is now told to stay indoors.
12:10AM: Names are believed to have been confirmed for the two men. The dead suspect is Tamerlan Tsarnaev, a boxer who moved to the USA in an attempt to make the US Olympic team. He is believed to be 26 years old. The second suspect is named Djohar Tsarnaev, and is believed to be 19 years old.
12:12AM: WCVB has spoken to girl who knew one suspect at school and says he was quiet. She was not close with the suspect. "It's crazy cause you never know what could happen next," she says of today's situation.
12:14AM: The name of the second officer shot has been released. He is 33-year-old Richard H. Donahue. He remains in hospital.
12:15AM: The FBI has released a wanted poster for the surviving suspect.
12:19AM: All taxi services in Boston have been suspended.
12:20AM: Brothers told person when they hijacked car at 4:30pm that they were the Boston marathon bombers. One brother apparently ran the other over or hit him with the car in the chaos of the ensuing police chase.
12:24AM: A man who knew Djohar in high school says he worked at Harvard as a lifeguard. "[We had] no evidence to believe that he would be capable of anything like this," he says.
12:29AM: Police are being warned to use caution if approaching Djohar as it is believed he may be wearing an explosive vest.
12:31AM: An uncle of the suspects, in Maryland, has told media "I wish they never existed."
12:37AM: A strong smell of smoke has been reported by several journalists as a convoy of police officers race to a new location. Media are being asked to move by police "for their safety".
12:41AM: Police have drawn weapons and are running along a street in Watertown.
12:45AM: Police have surrounded an address in Willow Park. SWAT teams are on the roof of a nearby building.
1:04AM: The AP reports "Father of Boston bombing suspect says son is accomplished medical student and 'a true angel'."
1:08AM: Police have released another picture of Djohar.
1:14AM: The boys' uncle Ruslan Tsarni is talking to media, saying the boys had been in US for seven or eight years. He has lived there 10 years. Family problems meant he didn't talk to them for 2-3 years.
1:45AM: The dead MIT officer has been named as 26-year-old Sean Collier.
2:05AM: A former high school teacher says he struggles to believe Djohar has committed the atrocities he is accused of.
2:26AM: US President Barack Obama is being briefed on the situation.
2:52AM: Police have been calling for a Russian interpreter and police activity in the area has increasedaround a stolen Honda CRV which has been found. Gathered media are also being told to move back.
3:06AM: Authorities being cautious of other pipe bombs which may have been planted. The interpreter may be needed for someone who is of assistance to the search, not necessarily the suspect.
3:50AM: Police have held a press conference where they announced the Honda CRV was present at time of carjacking and one of the suspects drove away with it. It has been recovered abandoned in Massachusetts. Reports a state police truck was stolen last night are false. An initial report of a possible subject is not Djohar.
Ruslin Tsarney has spoken to media again, saying "The only purpose here is to deliver our condolences and share grief with the real victims here."
"I never ever would imagine that the children of my brother would be associated with that."
He again stated he has not been in touch with the family for a number of years, and the last time he saw boys was December 2005.
When asked what could have provoked the attacks he commented "being losers... Not being able to settle themselves and thereby just hating everybody who did."
Mr Tsarney says the boys attitude has changed since he last saw them.
"Somebody radicalised them. But it's not my brother, who spent his life bringing food to their table."
"I respect this country, I love this country. This country, which gives chance to everybody else to be a human being."
"If I had been aware they were even slightly involved I would be the first one to bring them into responsibility."
Mr Tsarney also claimed the boys have never been to Chechnya and appealed to Djohar to give up.
"I say Djohar, if you are alive, turn yourself in and ask for forgiveness from the victims and the injured." "He put shame on the entire Chechen ethnicity."
4:25AM: Djohar's personal Twitter account has been found. A post in April 2012 references a trip to New York, matching up with photos taken of him in the city uploaded to a social media site days later.
On March 14 2012 he tweeted "a decade in america already, i want out".
4:30AM: A man is being arrested, but it is unclear if it is Djohar or a member of the public in an area they shouldn't be.
4:35AM: On April 22 2012, Djohar tweeted "Буду погибать мaлодым" - which when translated to English means "I will die young".
4:39AM: Police are going to undertake controlled explosions at an address which has been previously secured. Police say they have new leads in recent minutes they are following up.
4:43AM: On May 30 2012, Djohar tweeted: "i didn't become a lifeguard to just chill and get paid, i do it for the people, saving lives brings me joy #lifeguardoftheyear".
4:55AM: On September 2 2012 Djohar tweeted: "Idk why it's hard for many of you to accept that 9/11 was an inside job, I mean I guess fuck the facts y'all are some real #patriots#gethip".
8:33AM: 15 police officers were wounded in the overnight shoot out. Police are still going from door-to-door in Watertown, Massachusetts, in search of Djohar.
8:54AM: Police say that the search is 70 percent complete and asks for the patience of the public. A number of home-made explosives, including a pressure cooker bomb, has been found.
9:01AM: Uncle of the brothers say that their actions have brought shame onto the family and shame onto the Chechnyan ethnicity.
9:45AM: Witnesses say that Djohar "backed over" his older brother when making his escape.
The Massachusetts State Police say that the pair of brothers suspected in the Boston Marathon bombings spent the night in a Honda Civic and used it to carjack a Mercedes SUV. One of the brothers stayed with the carjacking victim for a few minutes then let him go. Authorities say that both suspects were in the Mercedes when they encountered police and hurled explosives at officers.
10:04AM: Colonel Timothy Alben, Superintendant of the Massachusetts State Police, has stated at a news conference that houses on 20 streets have been searched door-to-door. Tactical teams are being decreased although the police will continue to patrol the area.
10:06AM: The police do not have an apprehension and the "stay indoors" request has now been lifted, although the public has been cautioned to stay vigilant.
The FBI will continue their investigation.
10:15AM: State police have stated Djohar is the only suspect that they are pursuing at this time: "He is a very violent and dangerous person, and that is our primary concern."
10:28AM: The Massachusetts State Police say Djohar, the at-large Boston Marathon bombing suspect, fled on foot and may not have a car.
10:56AM: A few dozen shots are heard in Watertown and movement of police cars seen.
11:03AM: Large police presence converging on neighbourhood. Ambulance seen travelling quickly.
11:08AM: Dozens of armed police officers have been seen with their guns pointed in the direction of a house. State police are telling residents to stay indoors.
11:10AM: Police are reported to have the suspect cornered off in Watertown. Police are reported to be firing gas to try and get him to come out or for him to pass out.
11:20AM: Heavily armed officers are reported to be advancing towards certain houses. Officers are huddled around trees and standing near their vehicles. Law enforcement agents are also in the area, waiting to see what happens next.
11:24AM: Bus with approximately 10 police officers have arrived in the area. Police are waiting in groups for further instructions. Ambulance is on standby.
11:26AM: About 10 residents are being evacuated from their houses, including a number of small children.
11:37AM: The bomb squad are reported to be in the area. Police are being extremely cautious in approaching the suspect, as the suspect may be carrying explosives.
11:40AM: CNN has reported the FBI interviewed the now deceased older brother in 2011 but did not find any cause to continue investigating him.
11:46AM: The possible suspect is believed to have been cornered and pinned down in a boat in a Watertown backyard.
12:00PM: Reports of at least eight loud bangs could mean police are trying to "flashbang" the suspect out by stunning and disorienting him, or trying to gas him out.
12:08PM: The suspect is cornered in a boat in a dry dock in the backyard of the property. Police are taking caution in case there is fuel in the boat.
12:20PM: People in the area have heard police yelling to the suspect, urging him to come out on his own terms, with his hands up.
12:40PM: Three people have been taken in for questioning by police after a search warrant was issued for a property in New Bedford, Massachusetts.
12:43PM: A man has been seen walking from the property with police. Residents yelled out to the police "is that him?" and a police officer called out "yeah".
12:45PM: A police vehicle has been seen leaving the scene.
12:46PM: Boston police tweet that the suspect is in custody.
12:48PM: Suspect will be taken to the federal courthouse to be booked and processed. It is unclear whether the suspect is injured, but he has "unspecified medical needs".
12:50PM: Police begin an "aggressive" sweep of the area.
12:51PM: Suspect could be arraigned tomorrow, depending on his medical condition.
12:52PM: Two federal law enforcement officials confirm the identity of the suspect. He is the younger brother.
12:58PM: Ambulance and bomb squad vehicles begin leaving the scene, to cheers from residents.
1:00PM: Police confirm the suspect was injured.
1:03PM: A local resident describes how applause burst out when the suspect was taken into custody.
1:04PM: CNN describes scenes of jubilation and relief. Residents cheer every time a police vehicle drives past. Police are shaking hands with each other.
1:09PM: Suspect Dzhokhar Tsarnaev has been taken to hospital after being taken into custody.
1:11PM: Police continue to sweep the area where the suspect was found.
1:17PM: Residents describe a "tremendous sense of relief." "It's just incredible." They say it was terrifying to learn the suspect had been hiding out in their area.
1:18PM: Boston "is a very resilient city," says a local. "We will recover."
1:20PM: Boston mayor Tom Menino tweets a picture of himself shaking hands with the Governor. The caption reads "teamwork".
1:22PM: An analyst describes the security operation as "textbook", "brilliant".
1:24PM: FBI has confirmed it had questioned the suspect in the past. Debate is expected as to why he wasn't recognised as a security threat.
1:26PM: Suspect's uncle says "I'm glad they got him alive".
1:30PM: Suspect is apparently not in good medical condition.
1:32PM: "We are so grateful to be here right now. We are so glad to be able to bring closure," say police at a press conference. "We are entirely grateful for the outcome here tonight. We have a suspect in custody."
1:33PM: Police press conference continues. "We're exhausted, but we have a victory here tonight."
1:34PM: Governor Patrick pays tribute to the many professionals and members of the public who played a part in the operation. "We thank you." "Tonight we are all going to rest easy."
1:35PM: Attorney general speaks of the "horrific" and "heroic" events that have unfolded over the past 24 hours. "This will continue to be an ongoing, active investigation."
1:37PM: "Thank you, thank you, thank you," says Boston mayor Tom Menino. "People will be able to sleep tonight because of the work of these individuals."
1:42PM: President Obama is expected to speak shortly.
1:45PM: Police chief describes how suspect was found in boat. A member of the public called the police after discovering a man covered with blood in a boat in his backyard.
1:47PM: Police say at this point in time the threat to Boston appears to have been removed.
1:48PM: Police confirm suspect is in a serious condition in hospital.
1:49PM: Police say gunfire was exchanged while the suspect was in the boat, but it is unclear whether he was shot. It is believed he had been injured the night before.
1:49PM: "This is a very dangerous time in the world," says police chief.
1:50PM: Police chief says it is not clear exactly how the suspect was removed from the boat.
1:51PM: Media question whether suspect could face the death penalty. Attorney general says all evidence will have to be considered before any decisions are made.
1:54PM: Police press conference ends.
2:02PM: It is revealed a robot was used to remove the wrapping from the boat to expose the suspect.
2:05PM: President Obama begins addressing the nation. "Tonight our nation is in debt to the people of Boston."
2:05PM: "We have closed an important chapter in this tragedy," says President Obama.
2:06PM: "We owe a tremendous debt of gratitude," says the president.
2:07PM: "I have instructed the FBI... to continue to deploy all necessary resources to defend our citizens."
2:08PM: "They failed because the people of Boston refused to be intimidated. They failed because Americans will not be terrorised."
2:10PM: "Tonight we think of those who are wounded." Those who were killed lost their lives in "duty for their country."
2:11PM: President Obama also pays tribute to those wounded and killed in the Texas fertiliser plant explosion.
2:12PM: President Obama ends press conference.
2:15PM: Legal analysts discuss whether or not the suspect had his rights read to him after being arrested. He may not have been medically well enough to answer questions.
2:17PM: Boston police commissioner Ed Davis says the suspect was "severely injured". A photo is revealed of the suspect being taken away in the ambulance.
2:18PM: Police commissioner says it is unclear what motive the brothers had for their attacks.
2:20PM: The brothers are believed to have been associated with an extremist Islam group. Federal government is concerned about hate crimes, and is warning the public not to make attributions about wide groups of people. Extremists are not representative of Islam as a whole, they say.
2:23PM: The brothers' motives may be revealed by studying their online activity.
2:27PM: Hundreds of residents celebrate in the streets as police continue to leave the scene.
2:30PM: Former New York mayor Rudy Giuliani says the resilience of Boston is "remarkable". He compares it to the New York resilience after 9/11.
2:38PM: A former friend of the brothers says the older brother disappeared about two years ago. He can't believe what happened - "that's not who we knew growing up". Older brother was very proud of his boxing.
2:40PM: Former friend says younger brother was "a normal kid". He says he was more popular and outgoing than his older brother.
2:48PM: No further information yet on medical condition of suspect, who is in hospital.
2:53PM: A former beauty client of the suspect's mother says the family home was always very busy. She says a year or two ago she noticed a change in the mother, who started dressing and behaving differently.
2:55PM: The mother allegedly believed that 9/11 was a government-led conspiracy designed to stir up hatred for Islam.
2:57PM: Suspect Dzhokhar Tsarnaev is being treated for his injuries at the Beth Israel Deaconess Medical Center in Boston.
3:00PM: Live updates concluded. Please check here for further updates.
The shooting comes just days after Monday's twin bombings at the end of the city's iconic marathon, and the day after the United States senate voted against introducing stricter background checks for gun purchasers.
3 News / AP