♪ ♪ (indistinct chatter) >> More than 20 years, we are suffering from rockets here.

>> JON SWAINE: Before October 7, had anyone intruded?

Had they come into the kibbutz, or was that the first day that people... >> This is the first day.

>> SWAINE: Yeah.

(voiceover): I met Israel Lender in Kfar Aza, near the border with Gaza, in the weeks after the Hamas massacre that left around 60 of his neighbors dead.

>> This is my house.

You see now they covered all the... glasses that was broken.

From here, they can see all the streets.

>> SWAINE: So they came here, they went on your roof?

>> Yes.

>> SWAINE: So they could have a view of the rest of the kibbutz.

>> Yes, yes, yes.

>> SWAINE: He told me Hamas gunmen stormed his house shortly after sunrise, and turned it into a sniper's nest.

He hid with his wife in a nearby room for 36 hours.

>> The door was closed, the windows was closed, and the glass was open.

So I could hear everything.

(distorted speech and gunfire) (indistinct shouting, radios beeping) (indistinct shouting) >> (speaking Arabic) >> (screaming) (boom echoing) >> Terrible.

You can't, you can't, you can't... think about it.

♪ ♪ You can't believe it.

>> SWAINE: Mm.

>> You can't believe it.

You can't imagine it.

What they did here... >> SWAINE: Mm.

>> Nobody can do.

They build a big wall.

>> SWAINE: Mm-hmm.

>> They said to us, 40, 40 meters in the ground, with the sensors that nobody can-- and six meter up.

>> SWAINE: They said "This will protect you."

>> Yeah.

We believe that this can protect us.

>> SWAINE: They just broke through.

They came through.

>> They came through.

♪ ♪ >> (speaking Arabic): >> SWAINE: On the morning of October 7, more than a thousand fighters from the Palestinian militant group Hamas broke through the 20-foot-high barrier that has long-separated Israel from the Gaza Strip, a densely populated enclave that is home to more than two million Palestinians.

The 37-mile long barrier was completed in 1996 and is outfitted with cutting-edge surveillance tools, a deep underground concrete layer to block Hamas tunnels, and remote-control machine guns above ground.

After a billion-dollar upgrade in 2021, Israeli officials dubbed it "the Iron Wall."

>> (speaking Hebrew): (explosion booming) >> SWAINE: But in a matter of minutes, Hamas was able to breach the fence in around 30 locations-- the start of what would become the deadliest assault in Israel's history.

At least 1,200 people were killed; 240 were taken hostage.

♪ ♪ The attack triggered a catastrophic war in Gaza that has killed thousands of Palestinians so far.

Israel has vowed to destroy Hamas, which has controlled the territory for years.

>> Broadly, the fighters entered at 6:40 A.M. >> SWAINE: Uh-huh.

And that's the same incident, just from the other side of the street.

>> Exactly.

>> SWAINE (voiceover): Soon after the Oct 7 attack, "The Washington Post" began investigating how the so-called Iron Wall could have failed so spectacularly.

Our team of reporters analyzed hundreds of videos, photos, and audio recordings from before, during, and after the attack.

With "Frontline," we spoke with witnesses on the ground.

>> We got hit with the first RPG.

>> SWAINE: And examined maps and planning documents recovered from Hamas fighters.

We took the visual evidence from October 7 and mapped it across southern Israel and inside the Gaza Strip, sometimes using the position of the sun to estimate when key events occurred.

What we found was a fragile barrier that gave Israel a false sense of security.

leaving it blind to its own vulnerabilities and to the meticulous plan taking shape on the other side of the fence.

(indistinct shouting) >> SWAINE: The attack began at dawn, around 6:15 A.M.

Videos recovered from Hamas fighters show them setting off from Gaza, and heading toward the fence, which has long been resented by Gazans who've been penned in by it.

(Hamas fighters shouting in Arabic) >> SWAINE: People along the road cheered them on.

(explosion booming) (shouting in Arabic) (rockets firing) >> SWAINE: Around 6:30, as fighters made their way to the fence, Hamas began firing a barrage of thousands of rockets at targets across the barrier.

♪ ♪ In just the first five minutes of the attack, there were red alerts for more than 30 communities near the Israeli side of the wall.

In Kibbutz Erez, less than a mile from the barrier, Ben Sadan, a member of the community security, had just woken up for an early morning bike ride.

>> (speaking Hebrew): >> SWAINE: So over there, we can see Gaza.

>> (in English): There.

>> SWAINE: Yeah.

And the, the security fence... >> Yeah.

>> SWAINE: You can see it running along there, and there's the towers with the machine gun.

>> Yeah.

It's the border.

>> SWAINE: Yeah.

>> On the left side, it's Gaza.

On the right side, Israeli.

>> SWAINE: And I think some of the earliest rockets came over just around here.

>> All around, all around.

(in Hebrew): >> SWAINE: From this hilltop, the next wave of Hamas's attack became visible.

Reconnaissance fighters on paragliders, soaring over the wall under cover from the rockets.

Videos we obtained show them landing in communities inside Israel, the culmination of a plan that had been years in the making-- and that, as we discovered, had been brewing in plain sight.

>> When I first saw this video, I was like, "Oh, this is video from day of.

How did they get this produced out so quickly?"

And then, once you look closer... (clicks tongue) Oh.

It's obviously a training video.

♪ ♪ >> SWAINE: Our investigation found multiple videos recorded by Hamas detailing their planning measures.

Some were posted on social media before the attack, visible to all.

We found videos of militants training for attacks on mock-ups of Israeli compounds.

Videos posted soon after the attack showed they had also been practicing the use of paragliders.

Hamas had also been expanding their training camps, activity that was visible in widely available online maps.

But this evidence was largely ignored or dismissed by Israeli intelligence and the military, our investigation found.

♪ ♪ Michael Milshtein is a former head of the Palestinian department for Israel's military intelligence.

He has been strongly critical of their missteps leading up to October 7.

Israel knew about, about the whole plans, because, you know, Hamas didn't hide them.

It was on public, on their internet sites, on their TV, everywhere.

From the operational tactic point of view, October the 7th, we-- Israel, IDF-- didn't... face any, any surprise over there.

>> SWAINE: Were there specific warnings that something like this could be coming?

>> Well, according to reports in the Israeli media, there was very focused reports about the whole plan, the, the whole offensive plan, that promoted... and actually the data, the reports itself, were known, even to senior ranks, senior figures in IDF intelligence.

But the basic assumption, the basic assessment in the intelligence, was that those are only trainings or theoretic... theoretic attempts.

But we are not speaking about something which is very feasible.

♪ ♪ (Hamas fighters speaking Arabic) >> SWAINE: The heart of Hamas's operation on October 7 was the stage that their videos call "the blinding plan," aimed at severing the connections to Israel's surveillance and security system.

♪ ♪ Israel uses seven "Skystar" surveillance balloons to monitor hotspots along the Gaza fence.

The balloons carry a long-range, 360-degree camera.

But the model of camera that Israel uses on the balloons is relatively old and is no longer made.

On the morning of October 7, we found that three of the seven balloons had been shut down for maintenance.

(indistinct shouting, weapons firing) Video from the attack shows one of the remaining balloons.

A source told us it had been cut loose by the militants.

The balloons are part of a system that includes surveillance and weapons towers.

Visuals and other data from the towers are fed into monitoring centers inside Israel, including one near Re'im.

>> It doesn't matter how many combat soldiers they are.

If they don't know where the enemy is, they can't fight the enemy.

>> SWAINE: Rotem Horowitz spent two years monitoring the camera feeds at Re'im before completing her military service last spring.

Three of the balloons were out of service on the day, they weren't working.

>> Mm-hmm.

>> SWAINE: The cameras needed to be repaired, but they're old and out of production.

>> Yeah.

So... >> SWAINE: Is that a big problem?

>> I personally think it is.

They were first brought into use in 2006, and... ever since then, it's kind of been the same system.

It doesn't work very well during rough weather, like, only when weather conditions are perfect.

>> SWAINE: Do you remember people sending up warnings that, you know, these balloons are getting out of date, some of them aren't working, they're not working in bad weather?

>> Yeah, I know that the surveillance operators on the balloon have... as long as I've been there, you know, I served there-- we've been complaining about how the balloons see and, like, in general, their quality.

>> SWAINE: Mm.

>> Ever since I can remember.

>> SWAINE: The balloons are supplemented by surveillance towers containing HD cameras, laser and infrared sensors, and radars, and can see people for almost six miles away, according to the manufacturer.

Other structures, called Sentry Tech towers, are topped with Samson weapons stations, which feature machine guns and sensors.

They're positioned every few hundred yards along the barrier and outside key military facilities, and are nicknamed "Roeh-Yoreh," Hebrew for "Sees Fires".

Once the sensors send an intruder alert, IDF personnel can fire the 50-caliber machine guns by remote control.

>> We have to really make sure that we can firmly see a weapon and a threat before we can actually do anything with it.

So usually, like, if someone's getting close to the fence, we use it to kind of-- not shoot at them, but shoot near them to kind of, like, scare them away.

Like, "Don't come close."

You know, we're not going to touch them if they don't come close.

The moment they're showing they're a threat and they're coming close, that's when we start to act.

>> (speaking Hebrew): >> SWAINE: Video from one of the sentry towers on October 7 shows it firing on a group of Hamas fighters as they approached the fence near Kissufim.

But that's not what happened elsewhere.

Hamas fighters had come prepared to evade the towers, and documents recovered after the attack reveal a deep and detailed knowledge of Israeli defenses.

In this one, they specifically note the locations of surveillance systems.

Fighters also carried with them open source satellite imagery annotated with coded locations of key structures along the wall.

Armed with this information, Hamas carried out their blinding plan using unmanned drones equipped with cameras, to drop explosives on installations like this surveillance tower in the community of Be'eri.

Of the sentry tech towers marked on the map, we verified videos of at least two of them being attacked.

This one, located near Kfar Aza, was attacked twice by Hamas drones.

Incendiary explosive devices with fuses were dropped on the camera and weapons system.

Some of the training videos we found posted online show that these drone maneuvers had been well-rehearsed.

(bomb bursting) Other videos from the 7th show towers being attacked with rocket-propelled grenades and gunfire.

It's hard to tell just from the video evidence how badly damaged the installations were.

Hi, thank you so much for your time, I really appreciate you coming and seeing us tonight... (voiceover): But retired Colonel Dany Tirza, the former head of the Israeli military's fence administration, told me Hamas's blinding plan drastically undermined Israel's ability to respond to the attack.

>> That was a real failure, because they succeeded to cut the command system.

The command system of all this area... >> SWAINE: Mm-hmm.

>> ...was built on one control system, and they succeeded to cut it.

And therefore, we couldn't use helicopters, because according to the Israeli system, the helicopters cannot shoot if there is not someone on the ground that show them where are your forces, where are the other side forces.

So they came, but they couldn't shoot, because they didn't know who and what is going on there.

>> SWAINE: In 2021, when the latest upgrade... was unveiled, some of the political and military leaders made very firm, quite bold, claims for the barrier.

They said, "This will protect "the residents in the south.

Hamas will not get in."

And... Was that a mistake, to promise those things?

>> Of course it was a mistake.

We really thought that we are building a very good infrastructure that will help to save the lives of the Israelis.

Unfortunately, it didn't work.

>> SWAINE: He said the attack exposed a fundamental misconception about the fence.

>> It was built against people that will try to cross it.

It wasn't built against army or against a lot of people that are coming in one time.

>> SWAINE: Were you surprised-- you, personally-- surprised at how quickly they were able to blast through and make it into the bases and beyond?

>> I myself was not surprised that they crossed it so quickly, because defense is not built for such fighting.

It was built for another thing.

If you want to stop an army, you are doing it with army tools.

If you want to stop one, two, three terrorists, you're doing it with soft tools, like what we did.

We didn't thought that there will come a terror army from the other side, that were crossing at the same time, big groups, and we were not prepared for it.

♪ ♪ >> SWAINE: The Israeli government says Hamas broke through the fence in around 30 locations.

We obtained videos from 14 of them.

♪ ♪ The videos show trained Hamas fighters using a range of explosives and munitions to blow holes in the fence and its concrete barriers.

(explosion blasting) (indistinct yelling) ♪ ♪ It took them only minutes.

♪ ♪ By around 6:40 A.M., Israel's Iron Wall had largely crumbled.

♪ ♪ ♪ ♪ In the weeks that have followed, Israel's military and intelligence establishments have come under intense criticism.

A spokesman for the Israeli Defense Forces, Lieutenant Colonel Peter Lerner, agreed to speak with me at a military base in Tel Aviv.

Hamas has published several training videos which appear to show fighters in the months before practicing specific tactics that were then used on the day, blowing up fences, paragliding, and so on.

Did Israel not see this?

>> I mean, we're looking at what exactly transpired before the 7th of October, and there will be a time when the IDF will be doing that soul searching that is required, and the IDF will review that, and those that need to take responsibility will have to take responsibility.

>> SWAINE: What do you think October 7 says about the integrity of that barrier?

>> So, the barrier itself is a concept that was perceived to be a strong line of defense.

And any line of defense can only withhold a certain amount of pressure.

I think the question is not necessarily what is the barrier, but what was the threat assessment?

And these are the types of questions that we will be asking.

These are the types of questions that, that the answers to the residents of those towns of the Kibbutzim, we owe them... clarification, and, and... accountability for the failure of not the fence, but the whole concept of operations.

And this, I think, is what the IDF will be looking into when we... when the war is over.

♪ ♪ (Hamas fighters speaking indistinctly) >> SWAINE: The Hamas fighters that broke through the fence that morning were bound for the military bases and communities along the border.

(gunfire) ♪ ♪ One group headed for Kibbutz Erez, where Ben Sadan and the rest of his security team had already armed themselves.

And watched with dismay as the fighters kept coming.

>> (speaking Hebrew): >> SWAINE: And they're carrying weapons?

>> SWAINE: What kinds of things are they carrying?

>> SWAINE: How many of them were there, and how many of your men were there?

>> SWAINE: He told me the combat lasted for three hours.

After these few hours of fighting, what happened next?

♪ ♪ >> SWAINE: Sadah and his team had avoided the potential massacre.

>> Breaking news out of Israel... >> Chaos erupting in Israel... >> SWAINE: But other communities were overrun.

>> Hamas militants currently attacking citizens... >> Shooting at people on the streets, attacking troops... >> SWAINE: At 7:01, the first Hamas gunmen broke through the gate at Kfar Aza.

>> We are in kibbutz Kfar Aza.

>> SWAINE: More than 250 others would follow throughout the morning.

>> You can see this massacre.

It smells of death here.

♪ ♪ >> SWAINE: Some of the fighters wore body cameras, and the videos recovered later show the rampage through the kibbutz.

>> (speaking Arabic) (distant weapons firing) ♪ ♪ >> So this is my place.

>> SWAINE: Yeah.

(debris crunching) >> What's left of my house.

I don't have a roof, and look, everything is black and... and burned.

>> SWAINE: Yuri Levin witnessed the violence that day, and told me he'd barely escaped being kidnapped and taken to Gaza-- a fate that befell many of his neighbors.

>> He is kidnapped.

He is also kidnapped.

>> SWAINE: And these are all friends of yours?

You knew everyone?

>> They kidnapped.

>> She kidnapped.

He is murdered.

He is also kidnapped.

Murdered, and two of them kidnapped, I think.

>> SWAINE: Yeah.

>> Yes, now I think I know.

And...

This is friends of me.

>> SWAINE: Across the street, a group of his friends were returning home for the first time since the attack.

(crying, heart beating) (crying, heart beating continues) >> (exhales) >> YURI (speaking Hebrew): >> INBAR (speaking Hebrew): >> ADI (speaking Hebrew): >> INBAR: >> (speaking Hebrew): ♪ ♪ >> SWAINE: Israel, can you tell me about who these people are in the pictures?

>> These pictures?

>> SWAINE: Mm.

>> This is our village team.

Football team.

They're called... the fox of the village.

>> SWAINE: The young men?

>> The Kfar Aza village.

Some of them died.

>> SWAINE: Show me.

>> Some of them... are kidnapped.

He's died.

And...

This is in Gaza.

This, two brothers are in Gaza.

His parent's house?

>> SWAINE: Gone.

>> It was destroyed.

He's lost his mother and father, and his brother.

You know, almost everyone has a connection for who's murdered, who's kidnapped, who's injured.

Everyone from here.

>> SWAINE: It's touched the whole community.

>> Yeah.

♪ ♪