JEFFREY BROWN:So how did we get to this dramatic point? Kwame Holman has our recap of the major events of this day.
KWAME HOLMAN: Nineteen-year-old Dzhokhar Tsarnaev escaped the early morning gun battle in suburban Boston that killed his 26-year-old brother, Tamerlan.
That set into motion an unprecedented manhunt, as a small army of local, state and federal officers fanned out through Boston and its suburbs. The city was brought to a near standstill. More than one million people were urged to shelter in their homes. Schools and mass transit were closed. Amtrak service was shut down into the city.
Massachusetts Gov. Deval Patrick spoke at 8:00 a.m.
GOV. DEVAL PATRICK, D-Mass.: There is a massive manhunt under way, a lot of law enforcement involved in that. To assist that, we have suspended all service on the MBTA, our public transit service. And that will continue until we think it's safe to open all or some of that.
We're asking people to shelter in place, in other words, to stay indoors, with their doors locked, and not to open the door for anyone other than a properly identified law enforcement officer. And that applies here in Watertown, where we are right now, also Cambridge, Waltham, Newton, Belmont, and at this point all of Boston, all of Boston.
This is a -- this is a serious situation. We're taking it seriously. We're asking the public to take it seriously as well and to assist law enforcement by following those simple instructions. We have got every asset that we can possibly muster on the ground right now. They are doing a terrific job and working in concert with each other, but we are going to need the public to help us help them stay safe.
KWAME HOLMAN: In Washington, the president convened a briefing in the White House Situation Room with almost a dozen top aides.
The search focused on Watertown, Mass., just west of downtown Boston. The string of events began yesterday afternoon when FBI agents showed images of two then unnamed suspects pictured at Monday's bombing and called them armed and dangerous.
A harrowing night then began a short distance from the site of Monday's bombings. Around 10:30, gunfire was reported on the campus of MIT in Cambridge. Authorities say a campus police officer, 26-year-old Sean Collier, was shot and killed by the suspects.
The Tsarnaevs then carjacked a Mercedes SUV elsewhere in Cambridge, police say. The two men took the driver to three ATMs, where they got cash, before releasing him. Police pursued the SUV into Watertown. That's where heavy gunfire and explosions were heard, captured on smartphone video.
IMRAN SAIS, Taxi Driver: We heard a loud boom, and then a rapid succession of pop, pop, pop. It sounded like automatic weapons. And then I heard the second explosion. And then there was the smell of something burning in the air. We were still going toward it, and then residents from the windows, they shouted, hey, it's gunfire. Don't go that way.
KWAME HOLMAN: Superintendent Timothy Alben of the Massachusetts State Police:
COL. TIMOTHY ALBEN, Massachusetts State Police Superintendent: The pursuit went into a residential neighbor -- neighborhood not far from here, where there was an exchange of gunfire between Watertown police, MBTA police officer, and suspects in this SUV.
During the course of that pursuit, several explosive devices were discharged from that car at the police officers. In 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.
KWAME HOLMAN: Police shot Tamerlan Tsarnaev. He was pronounced dead a short time later at an area hospital.
DR. RICHARD WOLFE, Chief of Emergency Medicine, Beth Israel Deaconess Medical Center: This was a trauma arrest, multiple injuries, probably, we believe a combination of blasts, potentially gunshot wounds.
QUESTION: How many gunshot wounds?
RICHARD WOLFE: Unable to count.
QUESTION: Multiple gunshots?
RICHARD WOLFE: Yes.
QUESTION: I'm sorry. I didn't hear the rest of that.
RICHARD WOLFE: And probably a blast injury also.
QUESTION: Blast meaning what?
RICHARD WOLFE: An explosive device, possibly shrapnel, thermal injury.
QUESTION: Can you describe where it was?
RICHARD WOLFE: It was pretty much throughout the trunk. It was multiple wounds.
QUESTION: Would it be -- would it be consistent with perhaps a bomb strapped to the chest? Would it be consistent with that?
RICHARD WOLFE: Unclear. I think the medical examiner will be able to kind of conclusively say that, but there were signs of more than just gunshot wounds.
KWAME HOLMAN: The brothers were of Chechen heritage and came to the U.S. about 10 years ago. A circuitous path took them through Dagestan, a volatile region in Southern Russia.
Twenty-six-year-old Tamerlan reportedly was a hip-hop fan and a Gold Gloves boxer. In an online spread of photos that showed him boxing, he was quoted saying: "I don't have a single American friend, I don't understand them."
Nevertheless, he was said to have hopes of securing a U.S. Olympic team berth. The younger Dzhokhar graduated from the prestigious Cambridge Rindge and Latin School two years ago and was enrolled at University of Massachusetts at Dartmouth. He became a naturalized American citizen last year on September 11th, according to several news organizations.
A high school acquaintance spoke to reporters.
WOMAN: I'm not -- not so sure what set him off like this. So -- but I don't know. I mean, I have never -- I didn't meet his brother. So, I don't know who his brother is. I don't know any of that sort. So, I'm not sure. I am just really caught off-guard with all of this.
KWAME HOLMAN: Another high school friend talked to ABC News.
WOMAN: My school is very diverse, very open and accepting. We just kind of -- he never -- he didn't really talk with an accent at all. He was pretty, I mean, American, I guess. He had a lot of friends. He was a relatively well-liked guy, well-known.
KWAME HOLMAN: On a Russian social networking site Dzhokhar Tsarnaev's world view was listed as Islam, and he'd apparently linked to Islamic and other websites calling for Chechen independence.
Late this morning, an uncle of the brothers spoke to reporters from his home outside Washington. Ruslan Tsarni said he had not seen either man in years.
RUSLAN TSARNI, Uncle of Suspects: I have just been following it from day one, but never, ever would imagine that somehow the children of my brother would be associated with that. So it is atrocity. We're devastated. We're shocked. And, again, I don't know, this family doesn't know how to share that grief with the real victims.
KWAME HOLMAN: Tsarni said the family was Muslim and were ethnic Chechens. He was unaware what, if any, military training the men had or what led them to allegedly commit the crimes.
RUSLAN TSARNI: If that happened, most likely, somebody radicalized them. But it's not my brother, who just moved back to Russia, who spent his life bringing bread to their table, fixing cars, fixing cars. I say Dzhokhar, if you are alive, turn yourself in and ask for forgiveness from the victims, from the injured, and from those who left. Ask forgiveness from these people.
We're not requiring forgiveness in this family. He put a shame -- he put a shame on the Tsarnaev -- on our family, Tsarnaev family. He put a shame on the entire Chechen ethnicity, because everyone now names -- they play with the word Chechen. So they put that shame on the entire ethnicity.
So that's what I would say. Turn yourself in. And whatever -- whatever one -- I mean, put yourself at the discretion of those who are here.
KWAME HOLMAN: The men's aunt, Maret Tsarnaeva, had a different take. She spoke to reporters in Toronto.
MARET TSARNAEVA, Aunt of Suspects: My first call to FBI, they couldn't have done this. Where are the evidence? All you're showing is the footage. Two guys are walking. And I found it strange. Tamerlan is walking in the front. Dzhokhar is in the back. Why wouldn't they come together, just, you know, together, as brothers, as I used to know them?
KWAME HOLMAN: The men's father, who lives in Russia, told the Associated Press that his son Dzhokhar was "a true angel. He is such an intelligent boy. We expected him to come on holidays here."