Original subtitles

(dramatic music)

Narrator: It's one of history's

Most gruesome mass-murders.

Victor: They didn't show any mercy or anything,

They just killed.

Narrator: A norse warrior tribe,

Ancestors to the vikings,

Massacred and left to rot where they fell.

Aldsdotter: That both children and adults were killed

And then they were just left.

Narrator: It was a death so degrading,

The attackers believed their souls

Were doomed to purgatory for eternity.

Victor: It wasn't enough just to kill him,

You wanted to destroy their afterlife forever.

Narrator: Now, using the very latest forensic technology,

A team of investigators is trying to crack

This 1,500-year-old cold case.

Dufay: This is a massive site.

What were they defending themselves against?

Narrator: Uncovering a story of extreme brutality.

Aldsdotter: It's ruthless.

It was a planned assault, and probably a surprise one.

Narrator: Of betrayal.

Dufay: This could actually be an inside job.

Narrator: And of a bloody struggle for power

That has haunted an island for centuries.

Victor: You could almost compare it with game of thrones.

This seems like the red wedding.

(dramatic music)

Narrator: The relics of the past hold secrets.

(stones crumbling)

Written in gold.

(metal clanking)

Stone.

And blood.

We can unlock them.

These are the secrets of history's greatest treasures.

(dramatic music)

The island of oland.

Just off the coast of sweden, on the edge of the baltic sea.

180 miles of windswept coastline.

One of the outposts of fifth century norse warriors.

400 years before their better-known descendants,

These were the ancestors of the vikings.

(waves crashing) (gentle music)

Dufay: The presence of cemeteries and graves,

But also artifacts and the archeological evidence

Show that 15,000 or even 20,000 people

Could have lived on the island in the mid-iron age.

Narrator: The island is home to 15 ancient ring forts

From around the fifth century.

Some in ruins, others fully restored.

With mighty round walls up to 12 feet thick,

They're unique to the island.

And for archeologist dr. Ludvig papmehl-dufay,

They embody the violent cult of ancient norse warriors.

Dufay: This kind of structure

Doesn't exist anywhere else, actually.

(mysterious music)

The presence of all these ring forts on the island

Give a clear association to a warrior ideology.

The iron age in scandinavia is a society

Where violence and warfare is normalized.

(warriors shouting) (swords clanking)

Narrator: But one ring fort,

Known as sandby borg, stands out.

According to centuries -old local folklore,

It's an evil place where bad things happen.

Dufay: Many people have told stories about how they have

Been told as kids not to go to sandby borg.

We've been constantly told by people

In the surrounding areas that,

"oh, my grandmother always told me

"this is a dangerous place."

Some have even used the word haunted place.

(wind blowing)

Narrator: For the locals, sandby borg was a no-go area,

A site tainted by chilling ghostly tales.

But nothing could have prepared the archeologists

For what they would find here.

Evidence of a 1,500-year-old norse power struggle

That culminated in a bloody massacre.

A gruesome testimony that the vikings' ancestors

Were every bit as blood-thirsty and ruthless as they were.

Dufay: We haven't seen such a massacre

In historical times since,

So it's a major event that was totally forgotten.

(dramatic music)

(gentle music)

Narrator: It's a mystery that began in 2011,

When an excavation at sandby borg quickly,

And unexpectedly, turned sinister,

As archeologists began to uncover human remains.

(ominous music)

(tool scraping)

Victor: We had three trenches, and in the first one,

We found a human tooth.

In the second one we found a human jaw.

Then we started to think, what is this?

Then in the third trench we found a pair of feet

And we realized that we had a whole body.

Narrator: In just three small trenches,

The team had found the remains of three people.

They suspected this wasn't just a chance find,

And that more bodies were hidden elsewhere on the site.

So, they called in a very special forensic investigator.

(woman whistles) (dog panting)

(compelling music)

German shepherd, fabel,

Is the world's first ever archeology dog.

Working with his trainer, sophie vallulv,

He specializes in sniffing out ancient human remains.

Vallulv: When we arrive at site, I let him run free.

We use gps.

By doing this we can see exactly where he's been searching.

When he finds the smell of human remains,

He lies down or indicates, as we call it.

He then gets his reward, which is a green ball.

(gentle music)

Narrator: Fabel's reaction to the sandby borg site

Caught even the most seasoned archeologists by surprise.

Vallulv: At first, he was overwhelmed by the smell.

The rest of the team were skeptic

Because he was just running around,

Indicating pretty much everywhere.

But when we then got the chance to excavate,

I think it definitely won them over pretty quickly.

(dramatic music)

Narrator: Fabel had located remains all over the site.

In total, the archeologists uncovered at least 26 bodies.

They had discovered a village of the dead.

Dufay: We find dead people everywhere.

This is something real, this happened here.

(mysterious music)

Narrator: The sheer number of human remains was alarming.

But even worse was how they died.

As the team examined the remains in the lab,

A startling pattern quickly emerged.

Victor: This is from a young teenager.

And parts of the neck pieces have been cut in two.

Narrator: For chief archeologist dr. Helena victor,

The bodies all showed signs of brutal violence,

Sharp blows from swords or axes.

Victor: This is the skull of a young man.

He was killed by a cutting wound to his head.

If I put this together, you can actually see the cut.

And the cut is from above,

So we think that someone was holding him down.

So this was a murder, an execution.

(ominous music)

Narrator: The bodies had one thing in common.

They had all been brutally murdered.

Dufay: We could clearly see that this is a violent event.

Even though 1,500 years have passed,

You get this strange feeling

Of being the first on a crime scene.

(dramatic music)

Victor: You can almost compare it with game of thrones.

This seems like the red wedding.

Narrator: Dozens of people, all viciously killed.

All discovered inside a fortified camp.

To piece together what happened 1,500 years ago

At sandby borg, the team would need to use cutting-edge,

Modern forensic analysis.

It would reveal a level of brutality,

The likes of which the archeologists

Had never seen before.

A systematic, cold -blooded massacre.

(dramatic music)

For centuries, locals have believed

The site of sandby borg,

On the swedish island of oland, was haunted.

A place of horrors.

Now, an investigation is revealing the truth

Behind the legend.

A fifth century site of mass death with at least 26 bodies

All bearing the scars of horrific violence.

But what could explain such carnage?

The extreme brutality suggests

This could have been the scene of a battle.

As this was a time of deep-rooted rivalry

Among warrior clans,

And norse society was wracked by ruthless warfare.

But the victims' bones tell a different story.

(woman speaking foreign language)

Clara alfsdotter is the team's lead osteologist.

Aldsdotter: I've never excavated anything like sandby borg.

We see a lot of sharp force,

Which you would expect in a battle,

But the injuries we've identified so far,

Several of them are towards the back of the body

And to the sides.

So, we think that this is more like an assault,

An attack on people that weren't ready to fight.

(somber music)

Narrator: The wounds are almost exclusively

On the victims' backs and sides.

None show signs of self-defense or fighting back.

And if this was the scene of a battle,

Experts would expect to find only men of fighting age.

(ominous music)

(children laughing)

Instead, they've discovered not only the remains of men,

But of women and children.

Victor: They have been killing all ages.

The smallest one is a baby that is around 1 1/2

To three months old, and the oldest person is around 60.

Narrator: Experts believe this wasn't a group

Of fallen soldiers, but the scene of a ruthless ambush.

But there is something strikingly odd

About how the victims were found.

None were buried.

Many were spread-eagled, with arms and legs sprawled out.

The position could give the impression

They were killed elsewhere and dragged here.

But other clues suggest they were left where they fell.

It's a puzzle the swedish archeologists

Had never been faced with before.

Aldsdotter: Archeological remains

Are almost always found buried.

That's different than when they are left over-ground.

And we lack the knowledge of over-ground decomposition.

Narrator: To crack the mystery,

Alfsdotter has traveled over 5,000 miles

To a cutting-edge facility at texas state university.

One that investigates what happens

To the human body after death.

It's known in the trade as a body farm.

Dr. Danny wescott and his team use donations

Of real human cadavers.

Wescott: We are interested in the processes of decomposition

And then anything else that can happen

With the body after death.

When you're looking at an archeological site,

You're seeing a snapshot of some point in time.

The research that can be done here can give you an idea

Of how you actually got that snapshot.

(mysterious music)

Narrator: Alfsdotter is observing body donations

Left to decompose in varying conditions.

Aldsdotter: I'm out here every second day

Looking at how the body decomposes

And how the bones move in different sized open spaces.

Narrator: Alfsdotter is carefully observing

One movement in particular.

What westcott and his team refer to as the bloat.

Wescott: The first thing that happens to you when you die

Is that bacteria multiply,

Causing the internal organs to decompose.

And one of the things that's produced is gas.

And so this gas causes bloating.

Narrator: Evidence suggests that the bloat

Naturally pushes the bones to spread out.

It's a phenomemon clearly seen in the bodies

In texas left to decompose out in the open.

Aldsdotter: Even though this body in front of us

Was placed with limbs extended,

They sort of contract a bit during bloat.

In sandby borg we actually have one skeleton

Very similar to what the bloated skeletons look like here.

Narrator: It's a startling match.

Several skeletons in sandby borg

Have exactly the same shape as the bloated bodies in texas.

Aldsdotter: There was a discussion

Whether that was a result

Of someone being dragged or arms held back or something,

But coming out here and looking at what actually happens,

It is quite likely that it's just the result

Of the actual decomposition process.

Narrator: For alfsdotter, this can only mean one thing.

The victims at sandby borg decomposed where they died.

Close examination of their arm and leg joints

Backs up this theory.

They show no signs of stress from being moved.

Aldsdotter: All the joints are still very neatly preserved.

We don't see any manipulation of the remains after death.

(ominous music)

Narrator: The evidence couldn't be more damning.

The victims were left to rot, exactly where they fell.

Aldsdotter: It seems that these people were taken unawares,

Just killed and that they were just left behind.

(wind blowing)

(gentle music)

Narrator: In just one building on the site,

Archeologists unearthed the remains of seven young men.

Dr. Ludvig papmehl-dufay wants to get a sense

Of what that brutal scene would have looked like.

At eketorp, a ring fort on oland

That has been completely reconstructed,

He and his students reenact where

And how the bodies in that house were found.

Dufay: The layout of this house is very much similar,

They are sort of standardized.

This is about 10 meters long.

And the houses at sandby borg are 12 or 13,

So this is a bit smaller, but otherwise it's very similar.

(mysterious music)

Narrator: Ludwig's students

Take the exact position of each victim.

Dufay: Feet just right inside the door,

You can bend your knees a little bit more like that.

Narrator: To help visualize the scene of the massacre.

Dufay: You can have your face over here.

And then thomas will illustrate a body

That was lying on his back here.

There was actually another body

Lying with feet on top of this body.

When you excavate bodies, that's gruesome enough,

But when you see it like this, it's a sort of living house.

It makes it really awful, actually.

But we're not making this up.

You can almost hear the sounds and panic.

(people screaming)

(fire crackling)

Narrator: Ludvig believes this cold-blooded murder

Of men, women, and children wasn't a random attack.

It was pre-meditated.

The killers planned to catch their victims

Completely off guard by attacking at night.

Dufay: We haven't seen any evidence of day clothes,

That could mean that parts of the clothing had been removed,

For example, belts.

Narrator: Most victims were found indoors,

Suggesting they were gathering at the end of the day,

Perhaps for an evening meal.

Dufay: The fact there were several people

Inside the same house

At one time could mean that they were feasting.

We found the bones from eight slaughtered lambs.

It's a meat prepared for eating.

Narrator: The killers meant to wipe out

The sandby borg community quickly and efficiently.

Aldsdotter: It's ruthless.

The aim seems to have been to just kill the inhabitants

As quickly as possible.

(people screaming)

Victor: They didn't show any mercy or anything,

They just killed.

(dramatic music)

Narrator: The team is faced

With a 1,500-year-old cold case.

The means of the crime seems clear.

A brutal attack with savage weaponry.

But now they need to establish the two other golden elements

Of homicide investigation, motive and opportunity.

(dramatic music)

Swedish archeologists are trying to solve

A 1,500-year-old murder mystery.

At the ancient ring fort of sandby borg,

Dozens of pre-viking warriors were brutally killed

And left to rot where they fell.

The death toll is shocking.

But what could have provoked the perpetrators

To wipe out so many people?

One theory is this was not a military attack,

But a robbery.

(gentle music)

But the team suspects a different story.

Because it wasn't just the victims' bodies

That were left behind,

But exquisite hoards of gold and fine jewelry.

Dr. Helena victor has been studying

The norse valuables found at the site.

The most precious of which are gilded silver brooches

With intricate mythical designs.

Victor: All of the brooches are unique and some of them include

Parts of what we think are old norse saga sort of mythology.

Narrator: The late fifth century style of these brooches

Has led experts to date the massacre to around 480 a.D.

Each one of these prized pieces

Would have been the sacred keepsake of the ruling family

Of a local tribe, passed on from generation to generation.

Victor: These brooches were worn

By high-born petty queens possibly,

And they were made to be seen.

It's like a crown.

Everyone knew your status when you were wearing this.

Narrator: This makes the number of brooches

Found particularly astonishing.

In total, the team has uncovered seven.

Victor: We have never found this many in one place,

Usually find one.

It was mind-boggling.

(mysterious music)

Narrator: But what could explain

So many brooches in one place?

For dr. Helena victor,

It suggests the highest -ranking members

Of a number of tribes may have come together

At sandby borg for what would be a fateful gathering.

Victor: Maybe they were meeting to form an alliance

Or negotiate for peace.

Maybe they were there to celebrate a wedding.

We don't really know,

But we do know that they probably never left,

Since they left all their jewelry behind.

And this is not the kind of stuff you forget.

Narrator: For the archeologists,

The presence of so many riches at the murder scene

Suggests the violent attack at sandby borg

Can't have been motivated by the lure of treasure.

Dufay: If you think this is a plundering act, for example,

If you attack a ring fort to plunder it,

You wouldn't expect to find

Extremely exclusive jewelry lying around.

How come they didn't take these valuables?

Narrator: And precious jewelry wasn't the only thing

Left behind by the killers.

The team also found the bones of sheep, dogs,

And other animals.

Victor: We find animals that had been starving

And have curled up in a corner and died.

Dufay: If you want to plunder a site,

Animals are valuables, as well.

But they have just been left there to starve.

(somber music)

Narrator: Even the ring fort itself

Would have been invaluable to anyone seizing it.

Sat on the very edge of the baltic sea,

It could have controlled valuable trade routes

For hundreds of miles.

(water sloshing)

But there is no evidence that anyone

Ever lived here after the massacre.

Dufay: They actually left the ring fort unoccupied.

The ring fort is a huge investment.

Why don't you take it over?

It's clear to us that this is not a robbery killing.

So, there must be something else.

(ominous music) (wind blowing)

Narrator: But if the motive behind the mass murder

At sandby borg wasn't military or a robbery, what was it?

The team believes this could be the scene

Of a hate crime.

The evidence lies in how the victims' bodies

Were treated after death.

From their research in texas,

They've established the dead

Were left to rot exactly where they fell.

It's unlike any post-mortem ritual

They've ever seen in norse tradition.

(birds chirping)

Lindholm hoje, in northern denmark,

Is a settlement and grave site.

Established around the time of the sandby borg massacre,

It was used until the viking era.

Norbach: Up here we have graves from 400 a.D.

And downhill we have graves from 1000 a.D.

And actually, it's the same society,

The same community burying their dead here.

(dramatic music)

Narrator: Dr. Lars christian norbach

Has spent much of his career piecing together

The sacred burial rites of ancient norse warriors,

Who believed that one's existence didn't end with death,

But continued beyond into the afterlife.

During the fifth century, the time of the massacre,

The dead were usually cremated.

(birds squawking)

Norbach: The burial process, of course,

You start with the dead body of a person,

And you make a cremation fire.

(fire crackling)

Narrator: There would also be grave goods,

Belongings the deceased used in daily life,

They would now take with them into the afterlife.

Norbach: Typical items found in graves here would be a knife,

A loom, a bowl, a snapshot of everyday life.

Narrator: The ashes were then buried under an arrangement

Of stones made to commemorate the deceased.

Norbach: Stone settings represent different

Symbols of belief.

For instance, the ship-shaped stone setting

Would symbolize the ship as you use it in your daily life,

But also the ship as a carrier

From this world to the afterlife.

Narrator: A proper burial, with cremation, grave goods,

And a stone setting, gave the deceased a good death.

One that guaranteed passage to the afterlife.

(ominous music)

But the dead at sandby borg

Were given none of these rituals.

Victor: Oh, these people got a really bad death.

Leaving the bodies behind

Without getting the proper rituals

To be able to get to the other side, it was a big disgrace.

And you destroyed their afterlife forever.

Narrator: Dozens of bodies all struck with lethal force,

Purposefully denied passage to the afterlife.

For the archeologists, it all suggests the atrocity

At sandby borg was an act of extreme hatred or revenge.

And the most damning evidence

Was found in the remains of one man in particular.

Victor: He was found in a very special house,

And he's the only one in this house, and he's an older man.

We think that he may have been one of the chiefs

Or maybe the chief, the boss of sandby borg.

(mysterious music)

Narrator: Like the other victims,

This chief was left where he died.

But his remains then fell prey to local animals.

Victor: His head is obviously missing.

We think that a blow to his head killed him.

That animals have been in here scavenging.

And when they scavenge they take parts of the body

And take them somewhere else.

Narrator: It appears the man fell

Into a burning fire after being slaughtered.

(fire crackling)

But it's what happened in the moments before he was killed

That reveals the full hatred behind his murder.

Victor: The jaw was the only think we could actually find

From his skull, and inside that jaw,

Someone has put four sheep teeth.

You don't normally find sheep teeth

Inside the mouth of someone.

Narrator: Sheep's teeth, forced into the mouth

Of the chief of sandby borg.

The team knew of a similar rite

That was practiced across europe at the time,

Where coins were placed in the mouth of the deceased

To pay for their journey to eternity.

Victor: To make sure that you get to the other side,

You can pay the ferry man.

We find a lot of valuables in the face area of bodies,

Like a coin, or a piece of silver, or something,

That you can use to pay to get to the other side.

(ominous music)

Narrator: But forcing sheep's teeth

Into the chief's mouth was a mystifying anomaly.

The team suspects it was to make sure

The exact opposite would occur.

Victor: By putting sheep teeth in the mouth, it's a negative,

It assures that the dead person can't get to the other side.

Narrator: Perhaps it was an absolute guarantee

He would linger in purgatory forever.

(fire crackling)

Victor: It wasn't enough just to kill him.

You wanted to make sure

That he would never get to the other side.

And that's the greatest humiliation you could do,

To everyone, to give them eternal trauma.

(dramatic music)

Narrator: The team now believe the killers

Thought their victims didn't deserve to reach the afterlife.

And that leaving them where they fell

Was a way of ensuring they would have a bad death.

But what could these wealthy victims have done

To ignite such fury in this ruthless attack?

Further clues found at the site

Now suggest a shocking new theory.

These fifth century norse warriors had collaborated

With a ruthless empire intent on dominating the world.

(dramatic music)

The violence inflicted

On the late fifth century norse community

At sandby borg has shocked archeologists.

Whatever happened here wasn't a simple land grab

Or a vicious case of plundering

The vikings would later become famous for.

(men shouting)

No spoils of war were taken.

Gold, precious brooches, even livestock were left behind.

No one seized the fort.

And no one buried the dead.

So what could have prompted such a barbaric attack?

A major clue may hold the answer.

Among the finds in and around sandby borg was gold.

(coins clattering)

Roman gold.

Victor: This gold coin is actually from the roman empire.

And you can actually read on it,

Because they have latin letters.

So, we can read which emperor it is.

Valentine iii.

(dramatic music)

Narrator: Valentinian iii ruled in the mid-fifth century.

During a period of deep political turmoil

For the western roman empire

Struggling to fend off persisting invasions.

(men shouting)

Jarrett: It's a troubled time for the empire

With a series of militarized groups

Moving in across the empire's frontiers.

There's a lot of movement going on in this period.

Narrator: This type of coin was called a solidus.

It was a high-value tender

Mostly used to pay members of the roman army.

Jarrett: Solidi are the famous coin, the prestige coin,

4 1/2 grams of 90% plus pure gold,

Used to pay most directly soldiers.

Narrator: Over 300 solidi were found dotted

Over the island of oland,

Many of which were around sandby borg.

But the island is hundreds of miles

Beyond the edge of the roman empire.

So how did the coins get there?

Could the victims of the massacre have plundered them?

Or could they have once been soldiers of fortune themselves?

There is one crucial piece of evidence

Suggesting the dead at sandby borg were skilled warriors.

A very special piece of weaponry was found at the site.

An arrowhead.

(gentle music)

As none of the dead show signs of having been killed

By arrows, it seems this didn't belong to the killers,

But to one of the victims.

Dufay: It was found in the street at sandby borg.

It has a really pointy end here,

And then this square section.

Narrator: Many arrows from the period

Found in scandinavia were used for hunting animals.

But the arrow discovered at sandby borg is different.

Dr. Ludvig papmehl -dufay suspects

This one was a piece of deadly roman weaponry.

Dufay: This is an arrow used by a professional warrior

Who had been taking part in roman armies.

(dramatic music) (fire crackling)

Narrator: Ludwig believes it was specially designed

To penetrate armor, thanks to technology that originated,

Not in scandinavia, but in rome.

(people chattering)

To prove his theory, he needs to test the arrow's power.

Can it puncture the most impenetrable armor

Of the fifth century?

(metal clanking)

Chain mail, an intricate mesh of small metal rings

Only vulnerable to the most piercing of killing weapons.

(people shouting) (metal clanking)

Dufay: The other types of arrowheads that we have found

At sandby borg that you commonly find in this period

Would be too wide to penetrate the chain mail.

And the idea with this small experiment

Is to try if this really pierces the chain mail.

(mysterious music)

Narrator: It's the ultimate test.

If the arrowhead pierces the foolproof armor,

It's evidence some warriors from sandby borg

Fought alongside the romans.

Dufay: So, here's our victim.

Narrator: The target, over 20 pounds of pig meat.

Dufay: There we go.

That's actually really heavy.

Cross them and tie them together.

Now we see if we can dress him.

Narrator: The pig meat and skin

Are used to replicate human flesh.

Dufay: I think that will do.

That's the body, and then we have the clothing.

And then the armor.

You think you can hit it?

Archer: No problem.

Dufay: Let's see.

(birds squawking)

Narrator: Is the arrowhead powerful enough

To perforate such heavy-duty armor

And deliver a fatal blow to the wearer?

(suspenseful music)

(arrow thudding)

(chain mail tinging)

Dufay: Oh, this is nasty.

Archer: Yeah, really.

Dufay: It's stuck, actually.

Archer: I feel sorry for the guy who would be inside here.

Dufay: Yeah, you can see, there's a hole there.

So, it definitely went through there.

(ominous music)

Narrator: The chain mail is no match for the arrowhead,

Which has pierced the woven metal,

And the flesh it was designed to protect.

Dufay: I think this arrowhead is actually a killer.

If you hit a target with this one,

No matter if he's wearing a chain mail or not, he will die.

(dramatic music)

Narrator: This arrowhead was lethal

In the hands of a norse warrior.

It's further evidence the warriors at sandby borg

Were guns-for-hire who had earned precious gold

By fighting for rome.

Victor: They probably got them

By going down to the roman empire,

Getting them as payment for being legionnaires.

They were probably known as strong and fierce warriors.

They could fight and they didn't have any alliances.

Mostly interested in a good story and gold.

(mysterious music)

Narrator: Not only were solidi received as payment,

Some were pierced, suggesting they were hung

Around the neck with pride.

Jarrett: Carrying one of these things around

Would be almost like a campaign medal, some kind of badge,

I guess, of having participated in those events.

(ominous music)

Narrator: The western roman empire finally succumbed

To its enemies in 476 a.D.,

Just a few years before the sandby borg massacre

Is believed to have occurred.

Did norse mercenaries return home from the war

With their riches, only to be seen as a threat?

And fall victim to a brutal massacre?

Victor: There were a lot of warriors around and sandby borg

Was very rich, powerful, and that became a problem.

Someone saw that the elimination of this ring fort

Seemed like a good solution.

(dramatic music)

(fire crackling) (people shouting)

Narrator: The riches and status the sandby borg tribe

Earned from working for rome may have contributed

To the motive for the massacre,

With jealousy and resentment

From their enemies leading to cold-blooded murder.

But one question remains.

This fort was specially designed to keep people out,

So how did the killers get in?

(dramatic music)

For centuries, the ring fort

Of sandby borg laid undisturbed.

A forbidden place in the eyes of locals

Who believed it to be haunted.

A home to evil.

The site lived up to its reputation when experts found

Bludgeoned bodies, all brutally ambushed and murdered.

The dead, among them wealthy mercenaries who had fought

For rome, were left to rot without a burial.

For a norse warrior, it was the ultimate bad death.

Victor: We can actually see how people were killed

Where they fell.

Nothing has been removed, everything is there,

It's a riddle.

(mysterious music)

Narrator: The discovery of seven luxury brooches

Suggests the highest echelons of norse society,

Possibly the heads of different tribes,

Were gathered together.

For anyone seeking vengeance,

It was the perfect opportunity to attack.

But the mighty fortress of sandby borg

Was built for defense.

So how did the murderers actually get in?

Dufay: It's a very strong fortification

With just a few gates.

Makes you wonder how did the perpetrators get into the site.

(dramatic music)

Narrator: To crack the mystery,

Dr. Ludvig papmehl-dufay

Has created a 3d blueprint of sandby borg

At the time of the attack.

Measuring 6,000 square yards,

It was bigger than a football field

And boasted vantage points to spot enemies from far away.

Dufay: What it does say is that this is a massive site,

With a high wall, it's quite impressive looking from afar.

If the enemy would come from the sea

You would see it from a very far distance,

So that makes it, I guess, even more strange.

(mysterious music)

What were they defending themselves against?

Narrator: This impenetrable fort

Gives the impression its dwellers had many enemies.

But surprisingly, the team found no evidence

Of any assault on the fortress.

Dufay: If they would take this by force,

You would probably imagine to find signs of attack.

We have done quite extensive metal detector surveys

And we actually did excavations here, as well,

And there's no traces at all of an attack there.

Narrator: For ludvig, there can be only one explanation.

And it could finally reveal

The identity of the perpetrators.

Dufay: It rather looks like this was done

By someone already inside or being let in.

So, this could actually be an inside job.

(water sloshing)

Narrator: The victims must have known the murderers.

And either the killers had accomplices on the inside,

Or they were welcomed in unsuspectingly.

Could they have been close neighbors on a vendetta?

Victor: Everyone knew everyone else on the island.

It's not that big.

They could have been allies

But then the power of greed started to grow.

Dufay: Was it like an internal struggle?

Maybe there's another elite group on the island

Deciding that the sandby borg people should be wiped off.

(dramatic music)

Narrator: The fact the bodies were denied

A traditional norse burial backs up this theory.

Were they deliberately left to rot where they fell,

Not just as a guarantee they wouldn't reach the afterlife,

But as a warning to others never to repeat their crimes,

Or face the same fate?

Victor: It must have been really distressing, traumatic even,

Because this is so much out of the social norm,

To know that they were still lying there.

Narrator: It seems the perpetrators forbid

Other islanders from accessing the site,

So they couldn't bury the dead, even if they wanted to.

And so while the other forts on the island of oland

Continued to be used, sandby borg became a moment of horror,

Frozen in time.

Victor: It was a great trauma for everyone

Because no one was allowed to come here

For a very long time.

Bodies were just decomposing in the houses,

And the walls in the houses

Also started to fall down all over the bodies.

(dramatic music)

Narrator: If the attack took place

During a gathering of elite heads of local tribes,

Were there traitors among them?

Were sandby borg's wealthy mercenaries

Seen as a threat by their neighbors

Killed and left as a cautionary tale to others

In an ultimate fight for control of the island?

Dufay: You get the impression that the perpetrators

Were using the massacre to make a statement of power.

Narrator: Eventually, the descendants

Of these surviving norse tribes would become

The viking raiders of the middle ages.

(men shouting)

Victor: The people who did this probably won this internal war,

Or this power struggle.

(dramatic music)

Narrator: Silenced for centuries,

Sandby borg has long been cursed

By the mystery of its inhabitants' bloody demise.

The chance discovery of bodies and jewels

Has brought the ancient site back into focus.

But the discoveries may be just the beginning.

Only a fraction of the site has been excavated so far.

And experts believe the grim discovery

Of around 30 bodies is the tip of the iceberg.

Possibly hundreds more victims

Are still waiting to be found.

Victor: We have only excavated less than 10%,

But we already have found human remains all over.

And there's still a big mystery, we have a murder,

We have a massacre, and we want to know more.

Narrator: The team has discovered

That the legend of the haunted fort of sandby borg

Is more than just a folk tale.

The legend is real.

A modern memory of a 1,500-year-old mass slaughter

That has lingered as centuries passed,

The fort crumbled and even their descendents,

The feared vikings, faded into history.