Original subtitles

♪♪

Blitzer: We're following the breaking news,

important breaking news, out of Boston.

A pair of bombings rocked the finish line

at the historic Boston Marathon.

Abbott: I had been kind of catapulted through the open doors inside.

Silva: It was just full chaos, at that point.

Gregory: First responders rushing over, not knowing if a third

or a fourth or a fifth bomb was getting ready to go off.

[ Explosion ] Abbott: I remember thinking, "I could die here."

Blitzer: Clearly an attack.

We don't know who is responsible for this,

but we have now concluded this is a terrorist attack.

♪♪

♪♪

Hello and welcome to "How It Really Happened."

I'm Hill Harper.

Every year, on Patriots' Day, revelers from all over the world

take to the streets of Boston for the marathon.

But in 2013, this iconic event was brought to a shocking end

when, at 2:49 pm,

two brothers unleashed a horrendous,

unforgivable attack

on the unsuspecting crowds near the finish line.

Twin bombs were ignited

and instantly, hundreds of people were brutally injured,

and three killed.

Federal and local investigators teamed up

to track down the perpetrators of this appalling act

and, in less than five days, using state-of-the-art tech,

some old-fashioned police work, and a little luck,

they were somehow able to.

It all seems far-fetched,

even for the plot of a Hollywood film,

but it's all true.

Here's how it really happened.

♪♪

♪♪

Marathon Monday in 2013 started perfectly.

♪♪

It was a beautiful day.

♪♪

By midafternoon, the excitement of the elite runners was over

and the people who are running the marathon, at that point,

are people who are running for charities.

Chakravarty: They have a lot of supporters there.

They were probably six or seven people deep beyond the barriers.

People out there, rooting on

their friends and neighbors and family.

They were all there to see someone

crossing the finish line.

That day felt like any other day.

Jeff Bauman was at the marathon that day

with several of his friends.

Jeff remembers getting bumped into

by a guy who wasn't having a good time,

a guy who wasn't smiling.

Bauman: He was right next to me, you know, at that point,

and he had a bag and he had his glasses.

He just struck me odd.

♪♪

All of a sudden, probably 50 feet away,

at Marathon Sports,

there was an explosion, a burst, that shot up and out.

[ Explosion ]

Johnson: It was absolutely thunderous.

♪♪

Silva: That exact moment, I was on the finish line

on Boylston Street and I had my cameras rolling.

♪♪

Immediately, you knew something was very wrong.

♪♪

In just a second, everything changes.

Jeff Bauman is lying on Boylston Street,

feeling himself bleed out.

He thinks to himself, "Okay, this is where it's gonna end."

Tlumacki: I saw a runner had fallen on the ground.

I was confused.

I didn't know what was happening.

[ Camera shutter clicks ]

♪♪

I turned to the only colleague of mine

who was still on the photo bridge

and I said, "What do we do?"

And he looked at me and said, "I don't know."

I looked down the street and, at that moment,

the second bomb went off.

[ Explosion ] [ Screaming ]

The second bomb went off 12 seconds later,

about 550 feet down Boylston Street,

in front of a restaurant called the Forum restaurant.

♪♪

[ Screaming ]

♪♪

Pagan: We're right by the first explosion.

When that second explosion happened,

it seemed like it was just right there.

[ Explosion ]

There was a blue, hazy smoke that just hung over the area.

Once it cleared, you could see right down onto the sidewalk.

It just revealed the horror.

♪♪

Krystle Campbell was from Medford, Massachusetts,

a local girl who grew up in the area, fun-loving.

She was with her best friend right at the finish line.

I saw her through my viewfinder.

She had her arm hugging her friend

and, a few minutes later, she was dead.

♪♪

There was a mass panic, obviously.

[ Explosion ]

♪♪

People start scaling the barricades,

trying to tip them over.

At that point, my mind just calculated

everything coming together.

♪♪

We've had an attack. [ Panting ]

Man over radio: Secondary devices here!

There's secondary devices here!

♪♪

Elias: I ran up to the fence, looked over the side,

and all you saw were bodies.

Thirty feet across of just carnage.

♪♪

In the middle of all of this,

I remember seeing a little boy and he was sitting up

and he was just staring up kind of in our direction.

You thought, "Wow.

This isn't real."

♪♪

Then it was just full chaos, at that point.

People trying to pull the barriers back...

♪♪

...trying to assess what happened,

how many people were dead, how many people were injured.

My God. -The people closest

to the explosions

suffered the most significant injuries.

[ Sirens wailing ]

I remember seeing Carlos run across Boylston Street.

[ Sirens wailing ]

I managed to jump the fence, holding my flag in one hand

and my camera in the other hand.

The first person he came across was Jeffrey Bauman.

Arredondo: He was very much awake.

He was very pale, but he was bleeding on his leg.

That will forever be

frozen in my mind

because his eyes were open

and I couldn't believe that someone

who was so gravely injured could be conscious.

Carlos stayed with him, got him loaded into a wheelchair,

and then accompanied him to the transport

that brought Jeff to the hospital.

And I told him to hold on, hold on.

Bauman: When Carlos picked me up

and threw me into the wheelchair,

then I was like, "Alright, maybe Igonna make it."

Jeff ends up losing both of his legs below the knee.

One of the most iconic images from that day

is that picture of Jeff Bauman in the wheelchair

and Carlos Arredondo, the man with the cowboy hat.

But at the beginning, there was some suspicion

about Carlos being there so quick

and whether he was involved with what had happened.

He said his cellphone was confiscated by the FBI.

Authorities questioned him right away

and it obviously became apparent pretty quickly

that Carlos had nothing to do with it.

He became known as "the man in the cowboy hat,"

and became like very representative of the city

and everything that is good and kind.

But it goes to show how chaotic things were

in the aftermath of the bombing,

that someone so good, so kind,

could be considered a suspect.

[ Sirens wailing ]

Abbott: It was a tradition

for my friends and I to go every year.

At 2:49, I had just walked over to the Forum restaurant.

Immediately, I heard an explosion...

[ Explosion ]

...and kind of remember us

all looking in the direction of it

and, before there was a chance to react,

the second explosion occurred.

[ Explosion ] [ Screaming ]

[ Explosion ]

The next thing I knew,

I was on the ground inside of Forum restaurant.

I had been, you know, kind of catapulted

through the open doors inside.

And I remember, when I kind of came to,

seeing a lot of glass and blood on the ground

and smoke in the air and it was difficult to hear.

I remember seeing people, you know,

running towards the back exit of the building,

but my foot was in tremendous pain

and I knew I couldn't get up and run.

♪♪

♪♪

Very promptly, law enforcement, first responders,

and ordinary citizens rushed in to help.

She's mobile! She's mobile!

Get her out of here!

One thing that impressed me, over and over again,

in the immediate aftermath of the bombings,

was the extent to which absolute strangers

stepped up to help strangers.

Men and women whipping off their belts

and turning them into makeshift tourniquets.

I remember the manager of Marathon Sports,

where the first bomb went off, his window shattered,

grabbing things off of his shelves

to turn into makeshift tourniquets

to save people's lives.

[ Screaming outdoors ]

First responders rushing over,

not knowing if a third or a fourth or a fifth bomb

was getting ready to go off.

♪♪

Sydney and Celeste Corcoran are a mother and daughter

who were at the marathon as well,

near the finish line, when the bomb exploded.

I remember seeing

Celeste Corcoran laying on the ground.

Her husband, Kevin Corcoran, put a belt around her leg

and then, he got another belt from an onlooker

and put it around her other leg.

Her daughter Sydney was probably 20 feet away from her,

laying on the ground.

She was being helped by two men

who were applying a tourniquet to her leg

and putting pressure on it.

She remembered one man putting his head next to hers --

a stranger -- and saying,

"You're gonna be fine. You're gonna be fine."

Down the street at the Forum,

Heather Abbott was also helped by complete strangers.

I remember thinking, you know, "I could die here,"

and I started to call out for help.

As people ran by me, I thought, you know, "Who's gonna stop?"

I was very lucky that a woman named Erin Chatham stopped.

When she saw my foot,

she realized she wasn't gonna be able to do it on her own

and she went to get her husband.

It didn't take long at all before Matt Chatham came

and picked me up.

Matt Chatham is a former

New England Patriots football player.

I remember, as Matt was carrying me,

looking behind us and seeing a trail of blood follow us

and knowing that it was coming from me.

♪♪

The question became, "Who did this?"

Were they local? Were they from somewhere else?

At this point in time, there are no official suspects.

There's always a race

to try to get those folks before they can get away.

♪♪

Keilar: We have some breaking news.

Let's go down to Boston.

Apparently, there's been an explosion

-This is CNN. -at the Boston Marathon, I am told.

One of our producers, Matt Frucci,

is there on the ground, talking to us by phone.

What can you tell us, Matt?

Frucci: It was about 15, 20 minutes ago,

near the finish line on Boylston Avenue

here in Boston, when I heard two explosions.

♪♪

Rebekah Gregory was near the finish line

with her little son Noah.

♪♪

I remember that I was thrown back

and I could only lift my head

and I was frantically trying to figure out what was going on.

It looked like something out of a horror movie

and I just thought, "This is it.

I'm gonna die.

I'm gonna die right here on this pavement."

I was trying to figure out where Noah was,

but I couldn't really verbalize that.

I was just screaming and in pain.

I had never felt pain like that in my entire life.

I said a prayer in my head.

"This is it for me.

Take me, but let me know that Noah's okay."

♪♪

With my eardrums being blown out,

I shouldn't have been able to hear my little boy,

but I very clearly heard him screaming,

"Mommy! Mommy! Mommy!"

And I looked to the right of me

and Noah was in the arms of a police officer.

No one knew who each other were with that day

and so Noah and I were taken

to two completely separate hospitals.

Later, I saw that there was a photo taken of Noah.

I could just see the pain in my little boy's eyes

and just the confusion on what was happening.

♪♪

A gentleman came up and tied a tourniquet on my leg.

I remember justbegging the people in the ambulance,

"Put me out of my misery because I can't handle this."

[ Siren wailing ]

I knew my life would never be the same.

Man: At this time, we have all the victims off the scene.

Evans: I got to commend all the first responders.

I think, within 20 minutes, that whole scene was clear.

264 people were raced,

by any means necessary, to the hospital.

Of those 264 injured, 17 became amputees

and a few lost both their legs,

like Celeste Corcoran

and Jeff Bauman.

I thought there would've been a lot more fatalities,

to be honest with you.

As we've been telling you, there are three people dead

in these twin bombings at the Boston Marathon.

Such an iconic day in this city.

Patty: [ Crying ] You couldn't ask for a better daughter.

[ Sniffle ] I can't believe this has happened.

In addition to the terrible lost of Krystle Campbell,

the two other people killed that day

were Lingzi Lu and Martin Richard.

Lingzi Lu was a graduate student at Boston University.

Wedge: Her and her friend were actually going to the Apple Store

to get a piece of gear that she needed.

They were walking by the bomb site when the bomb detonated.

♪♪

And Martin Richard -- such a shame.

Martin Richard was just a young boy

who was at the event with his family.

He just happened to be up on the gate,

rooting people on, unfortunately,

when that second bomb went off.

The other day, I came across some photos

from a neighborhood party.

He was wearing a smile that could light up Fenway Park.

♪♪

These could be your best friends.

They could be your neighbors.

Those were our victims. These were real people.

These were Bostonians.

It was shattering.

Evans: I took it personal, as a marathoner,

as a resident of the city of Boston,

and as a Boston policeman.

To blow up our marathon, to blow up our city,

that got personal for a lot of us.

Man: Marathon's done. Those runners are just

gonna head out to the Commons, okay?

Marathon's done.

We're following the breaking news,

important breaking news, out of Boston.

A pair of bombings rocked the finish line

at the historic Boston Marathon.

Both explosions are captured on video

and somewhere in this crowd of race-day onlookers

is the person responsible.

Investigators just had to find them.

Blitzer: Clearly an attack.

No one yet has claimed responsibility.

We don't know who is responsible for this,

but, clearly, we have now concluded,

this is a terrorist attack.

I think what the experts could immediately tell

about this attack was it was meant to hurt people.

Then the question became, "Who did this?"

At this point in time, there are no official suspects.

Silva: Were they local? Were they from somewhere else?

Nobody knew. Nobody had any idea.

Why would anybody go harm innocent people?

This was an act of war against the city of Boston

and the nation, really.

We got to get who did this.

In any of these attacks, every second,

every hour, every day goes by,

you get a little bit further behind the perpetrators,

so there's always a race

to try to get those folks before they can get away.

President Obama called Governor Patrick immediately

and said, "You have our full support."

We still do not know who did this, or why,

but, make no mistake --

we will get to the bottom of this.

Any responsible individuals

will feel the full weight of justice.

The process of collecting evidence began immediately.

At this time, we are looking for the public's cooperation.

It was clear that they believed that video and photos

held the key to identifying the suspects.

♪♪

♪♪

My mom tells me the story about how,

when she walked into the ICU room,

that the doctor said I was in,

she came back and she begged the doctor.

She said, "You have to take me to my daughter

because she's not in this room."

My own mother -- my own mom -- didn't recognize who I was.

♪♪

We've had a horrific attack here

in Boston this afternoon.

The city was very much emotionally bruised

in the days following the bombing.

No other time in the city can I remember people were afraid.

We're asking that everyone be on a state

of heightened vigilance.

What's going on here?

They had no idea who they were looking for.

Wedge: Are they part of a cell?

It was a pretty terrifying time, to be honest with you.

We'll be working diligently to gather information

and gather all the facts

and bring those who are responsible for this crime

to justice as swiftly as possible.

There were thousands of people on Boylston Street, alone.

Where do you start?

♪♪

The process of collecting evidence began immediately.

There were three big categories of evidence...

Chakravarty: We knew that the universe of people

who likely did this were carrying a cellphone.

It was also possible that they used the cellphones

to coordinate with each other,

so we acquired the phone records for all of the phones

that were bouncing off of the towers

that were closest to the sites of those two blasts.

By collecting that data, you can then compare it

to phone numbers of known extremists

or people who are currently under investigation,

so we did that right away.

Next, forensically, you look to the crime scene itself

to reveal evidence that can somehow trace you back

to the identities of the people who have placed those devices.

♪♪

We are in the process of securing

and processing the most complex crime scene

that we've dealt with in the history of our department.

It was an enormous crime scene.

There was evidence everywhere.

Evidence was blown on top of cars, on top of windowsills.

I remember that evidence was found

on the sixth floor

of a nearby hotel.

There were blood samples, glass samples.

There was so much evidence on the scene,

they took over Black Falcon Pier,

which is the main warehouse

and loading dock on the waterfront.

The Black Falcon terminal evidence processing center

was the size of two football fields.

They built a massive grid

and they put all the evidence on that grid

to show where it was actually found.

Essentially reconstructing the crime scene.

They had the perfect space to be able to recreate it

because of the size of the space.

And then, for the pieces of evidence

that required more detailed analysis,

they loaded it on a plane twice a day

that flew back to our lab in Quantico.

So that cycle continued, hour after hour,

as we chipped our way through that crime scene.

The nature of the plume of smoke indicated it was some kind

of low-explosive type of powder,

things that would be suggestive of an IED.

Our lab went to work

at basically putting it back together,

looking at the components of the bomb,

what actually housed the explosive.

The investigation has yielded major new clues.

Sources now say the explosive devices

were apparently made from pressure cookers

hidden in backpacks.

We quickly determined that the bombs had been

constructed inside pressure cookers

and the explosive material was taken from firecrackers.

It was combined with things like ball bearings and nails

and pieces of steel to create shrapnel.

♪♪

The third component was the one that we thought would be,

probably, the most definitive,

but we knew would take the most time,

and that is culling through the volumes of video

[ Camera shutter clicking ] and photographic evidence...

[ Explosion ]

...from hundreds of thousands of people

taking photos and potential videos

and having surveillance cameras

that lined the Boston Marathon route.

♪♪

At this time, we are looking for the public's cooperation.

Evans: We appealed to the public.

You know, when you have 25,000 runners

coming down Boylston Street,

we knew a lot of loved ones had some video footage.

If there's any video, any photographic evidence,

if you can please contact the FBI hotline.

Boy, did we get a response.

We received hundreds of thousands of video submissions.

It's our intention to go through every frame

of every video that we have

to determine exactly who was in the area.

Chakravarty: We assembled teams to methodically go

through citizen-provided media.

They honed in,

looking for the proverbial needle in a haystack.

It was clear that they believed that video and photos

held the key to identifying the suspects.

♪♪

Investigators were under tremendous pressure.

Chakravarty: We didn't know who the perpetrators were.

We didn't know whether the attacks were over.

We didn't know whether they had more bombs.

There was definitely a mentality that it was a matter of time

before they may attack again.

We felt, "Let's get who caused this tragedy

before they hurt anybody else."

The weight of the world was on my shoulders,

as well as many others of my partners.

We will go to the ends of the Earth

to identify the subject or subjects

who are responsible for this despicable crime

and we will do everything we can to bring them to justice.

♪♪

Welcome back to "How It Really Happened."

We know now that the horrific bombings

at the Boston Marathon were carried out

by Tamerlan Tsarnaev and his younger brother Dzhokhar,

but neither had sent a threat in advance,

nor claimed responsibility immediately after the attacks,

so, in those first few days,

the number one question on everyone's minds?

"Who would do this?"

♪♪

[ Explosion ]

Davis: This cowardly act will not be taken in stride.

We will turn every rock over

to find the people who are responsible for this.

The demand for information and answers

is immediate and intense.

Who brought these devices in?

♪♪

The bombings occurred on tax day, April 15th,

so we, at first, thought it might be

some domestic terrorist group

that was opposed to the United States government

and didn't like paying taxes.

Just by looking at some of the characteristics of the bombing,

the people that came to mind were al-Qaeda.

MacLellan: You're thinking it's a huge, huge plot.

I said, "No one from Boston would ever do this

because they know what it means to us."

♪♪

Tamerlan, Dzhokhar, and the Tsarnaev family

came to the United States from Dagestan

in the early 2000s.

And they end up in Cambridge.

The Tsarnaev brothers were here with their father, Anzor;

their mother, Zubeidat; and their two sisters.

Chakravarty: They grew up in Cambridge.

They went to Cambridge public schools.

Cullison: I got to know them in 2003.

They had not yet really

acclimated to American society.

That's one of the reasons I became friendly with them,

because I was one of the few Russian speakers

in the neighborhood.

Dzhokhar was a much more passive child,

who would sort of sit at the back of the room and listen.

It was clear that Tamerlan was the prize horse of the family.

He was the one who they really placed a lot of hope in.

They were sort of interested in getting me to know Tamerlan

to sort of give him advice on where to go to school

and how to conduct himself

and insert himself into the U.S. society.

They simply didn't really have a very good grasp

of what was really possible in the United States.

Tamerlan had some idea that he was going

to make a lot of money and have a Mercedes-Benz,

so I sensed that there were some difficulties coming.

He had ambitions to become an engineer,

but he took a year off from school in order to box.

Tamerlan was a great boxer.

His dream was to fight for the United States Olympic Team.

Vasquez: He loved boxing.

It was his passion.

It was his outlet.

As he got older and he started fighting semi-pro, he learned

that he would never be able to be on the Olympic Team

because he wasn't an American citizen

and a lot of people told us that was a big blow to him

and to the family.

We don't know this for a fact, but our assumption is that some

of Tamerlan's frustrations about his life here

in the United States likely emerged

from his failure to progress as a boxer.

He continued working out at gyms and whatnot,

but it wasn't the professional path that he was on before.

♪♪

Armstrong: Tamerlan ended up meeting a young woman

named Katherine Russell.

She came from a wealthy family in Rhode Island.

Her dad was a doctor.

Her mom was a nurse.

Armstrong: Quiet girl, by all accounts.

They hit it off. Their relationship blossoms.

They fell in love and they started dating

and they got married.

She was raised as a Christian.

Chakravarty: But as she got closer to Tamerlan,

she became a Muslim.

She lived with the Tsarnaev family

in their home in Cambridge, in relatively close quarters,

and became pregnant and had a daughter.

One of the great mysteries

of the Boston Marathon bombing investigation is

what Katherine Russell might

or might not have known prior to the bombings.

She was never charged federally, but that remains, today,

to be one of the great unresolved mysteries

of the Boston Marathon bombing investigation.

♪♪

From all appearances, Dzhokhar seems

to have assimilated better than Tamerlan.

If you listen to Dzhokhar's teachers,

he was like Mr. All-American Boy.

Dzhokhar goes to high school

at a very prestigious school in Cambridge --

Cambridge Rindge and Latin.

It's a high school previously attended

by Matt Damon, Ben Affleck,

and Patrick Ewing.

Dzhokhar Tsarnaev was very popular in school,

very well-liked by his teachers, his friends.

He was Captain of the wrestling team.

Always a cordial kid, happy, peaceful.

There was nothing malicious about him.

Dzhokhar Tsarnaev matriculated

at the University of Massachusetts Dartmouth.

His grades started to decline precipitously

and he began to be more involved

with his friends, doing other things,

like smoking and distributing marijuana.

If you look at Dzhokhar's Twitter feed,

it's largely about trying to meet girls

and take naps and eat cheeseburgers.

I spoke to some former classmates, who would say,

"Oh, yeah, he's a chill guy."

Nobody expected this kind of thing to happen.

Dzhokhar seemed like he was destined for better things

than detonating bombs at Boylston Street.

[ Explosion ]

I'm sure, at one time in his life,

he was a very lovely, caring young man.

What he turned into, obviously, was --

We know what he turned into.

He turned into a monster.

On Wednesday, we got our first really

It was the video from a surveillance camera

positioned just outside the Forum restaurant.

Almost everyone turns in the direction

of the first explosion.

There's one person who doesn't turn.

There's one person who isn't surprised by that blast.

♪♪

♪♪

I think people had tremendous faith

that police would find the suspects,

but as each day went on,

it was hard to be patient.

Nobody knew what they were looking for.

Nobody knewwho were looking for.

♪♪

On Wednesday, April 17th,

we got our firstreally big break in the case.

I was called into my office by one of my agents

and he said, "Boss, take a look at this video."

It was the video from a surveillance camera

positioned just outside the Forum restaurant,

overlooking the scene of the second blast.

♪♪

In the foreground, it's people in the little forecourt

of the restaurant,

talking, snacking, having some drinks.

[ Explosion ]

At 2:49, there's a massive explosion off-camera.

You can actually see everybody in the Forum video

lurch forward just a little bit from the shock of the blast.

And then, in unison, everyone turns to the left.

DesLauriers: And shortly after, you see the second bomb detonated.

Right there at the Forum.

There's just an explosion of white

and everything disappears for a brief second.

And then, as that subsides,

it's just clouds and dust

[ Camera shutter clicks ] and carnage unlike anything you've ever seen.

It was just a horrible, horrible, horrible sight.

Investigators know, somewhere in this video, is the bomber.

They just have to figure out who.

♪♪

We looked at it over and over and over again.

They're looking for any kind of anomaly in that video

that shows that one or two people

are doing something differently than the rest of the people

who were there to watch the race.

Chakravarty: We had dozens of eyes staring at this video,

trying to track every single person.

And we played it forward, we played it backward,

played it in slow motion,

and we could not figure out who the bomber was.

We realized that, maybe if we got more information

about that same scene, at that same time,

it might help us.

And, sure enough, someone had submitted

a still photo from across the street

that was pointed at the exact location

of where the blast occurred

and that photo depicted, from a different angle,

a man with a white hat,

with a backpack at his feet.

They zero in on him.

"What is this guy doing?"

♪♪

In the video, you can see him

walk into the frame.

You see him with a backpack on his shoulder.

DesLauriers: He places that backpack down on the ground and stands there.

And then, you see him on a cellphone call

with somebody else and, about ten seconds later,

you see the concussive effect of the first bomb

going off down in front of the finish line.

♪♪

Hughes: Almost everyone turns in the direction

of the first explosion.

There's one person who doesn't turn.

There's one person who isn't surprised by that blast.

Evans: He walks away and he gets about ten feet from them

and, all of a sudden, this area blows up.

We knew he was responsible for it.

Suddenly, they're now able to see the trail.

♪♪

The challenge then became,

"Find out where he came from in the area."

So we assembledall from those businesses

to see how far away we could track that individual

and, sure enough, we find him coming down Gloucester Street.

That moment, that was the "Eureka" moment,

shall we say, in the investigation.

They were able to notice that he was trailing

an older, sort of stockier guy.

The other person who was accompanying him on the video

was wearing a black hat,

so we suspected that the other person

may have been responsible for the first blast.

♪♪

We knew, at that moment, that we had our two bombers --

"White Hat" and "Black Hat."

We just didn't know who they were.

♪♪

♪♪

Gregory: Noah spent five days in the hospital, initially.

He wasn't injured anywhere to the extent that I was

because he was sitting down on my feet

with his back up against my shins

when the bomb went off.

I took everything in the back of the legs,

the torso, and the left hand.

That's what shielded him.

He walked into my room and, without even missing a beat,

he came up to me and he just gave me a hug

and he said, "Mommy, we're gonna be okay, right?"

[ Tearfully ] I said, "Yeah, Noah.

We're gonna be okay."

It was that moment where I think I decided to survive...

♪♪

...because I had to give him exactly what he needed.

♪♪

Tapper: Here in Boston, President Obama attended an interfaith service

honoring the victims of Monday's bombing.

He told the congregation that,

"the spirit of the city remains undaunted."

If they sought to intimidate us...

♪♪

...to terrorize us,

to shake us from the values

that make us who we are, as Americans,

well, it should be pretty clear by now

that they picked the wrong city to do it.

♪♪

Now, it is Thursday.

We have the video of the two bombers,

but we don't know who they are.

For 24 hours, investigators kept those images a secret,

hoping they could figure out who they were on their own.

Because of the quality

of the video, we weren't able

to do some kind

of photo recognition

or other way to identify who they were.

We've talked to victims, to try to help us

with sketches and descriptions of the bombers.

None of that has brought us, really, anywhere.

We knew somebody out there, members of the American public,

would know who these two individuals were.

Then the question came, "Do we put it out

or do we hold onto it?"

There were several schools of thought there,

one being that we need to hold onto this video evidence,

to work covertly behind the scenes

to try to identify these individuals

and, if we release the evidence,

it might cause them to flee.

On the other hand, some of us -- myself included --

felt that this was theonly to identify these guys quickly.

♪♪

And they likely have more bombs

and what if more bombs go off in Boston

and we're left holding

this video evidence?

♪♪

But once we obtained

the video evidence from the Forum restaurant,

word of that leaked to the media.

They knew that investigators were looking

for two men with hats and backpacks.

Well, immediately, a lot of people started looking

at other photos and videos, in an attempt to identify

people they thought were these suspects.

People desperately wanted to know

who could commit such a terrible act of violence.

So, ultimately, what happened was,

the media leaked some photos

of people that were said to be White Hat and Black Hat.

There were a couple of local students that had backpacks on,

that were on the front page ofThe New York Post

and they were not the perpetrators of this crime.

It was causing kind of a chaotic, panicked scene

where unsuspecting, innocent people

were then being vilified in their communities.

We were really worried that those people were in danger.

And so, law enforcement agencies' hand

was kind of forced.

The decision time had come,

as to whether to disclose the images

of the white hat- and black-hatted persons.

♪♪

And Director Mueller decided that

that's what we would do that Thursday afternoon.

Wedge: President Obama finished his speech and left,

was wheels-up from Logan Airport.

They had a press conference and they released the photos.

♪♪

Today, we are enlisting the public's help

to identify the two suspects.

They had these big poster boards.

♪♪

They had several different photos of them,

different angles.

DesLauriers: They are identified as Suspect 1 and Suspect 2.

They appear to be associated.

Suspect 1 is wearing a dark hat.

Suspect 2 is wearing a white hat.

They were asking the public for any information

about who they might be.

No one should approach them.

No one should attempt to apprehend them,

except law enforcement.

We were hoping that a citizen

or somebody who knew these people

would call in and let us know who we should go after.

Somebody out there knows these individuals,

as friends, neighbors, coworkers,

or family members of the suspects.

I remember just everyone trying to figure out who they were.

Today, FBI officials released video and photos

of two male suspects in the Boston Marathon bombings.

The individuals were seen

walking casually away

from the Boston Marathon

after the bombs went off.

We had so many people hit the FBI website

in an effort to see the images

that we essentially crashed the FBI website.

And that was a critical, critical moment

in the investigation.

Now there's an all-out manhunt

for these two suspects.

♪♪

I think police hoped that, when they released these images,

the public would recognize these men, call immediately,

and they would arrest these two suspects.

And that's not what happened.

♪♪

There's always danger.

It was a gamble that law enforcement had to take

to get these guys.

What we feared actually happened.

Unfortunately, the bombers saw themselves on the screen

and they decided to go on to the next phase of their plans.

♪♪

Our worst nightmare happened that evening.

Berman: It was really a night of sheer mayhem here.

♪♪

Dispatcher: Officer down. Officer down.

All units. Get on it!

McCabe: We just had a carjacking.

Please help. Help me, please.

They have guns.

The brothers, of course,

proceeded to embark on a murderous crime wave.

I think the way it ended

was just as shocking as the way it began.

♪♪

The FBI had phone banks set up,

prepared for a massive wave of calls

that would identify the two bombers

known only to them as Black Hat and White Hat.

Tips started coming in.

But, before law enforcement

could do anything to act on them,

Tamerlan and Dzhokhar Tsarnaev

would gather up a handgun and a slew of homemade bombs

and head out into Boston, ready to unleash more terror.

Next, on part 2 of the Boston Marathon bombing.

Thanks for watching. Good night.

♪♪