Original subtitles

Tonight, a mysterious illness

strikes hundreds of government officials.

MARC POLYMEROPOULOS: In the middle of the night,

I woke up and the room was spinning.

I had a terrible case of vertigo.

I was frankly terrified.

Ongoing investigations raise more questions than answers.

MICHAEL HABIB: It's causing a lot of confusion, frustration,

and really starting to feel kinda like

they're in some sort of bad spy thriller.

Now, we reveal the top theories behind this bizarre epidemic.

SASHA INGBER: This could have been caused by something

that was already inside the embassy staff quarters.

JOHN TEFFT: These chemicals have been used

in some of the most deadly chemical attacks on the planet.

Could some foreign power have developed a new sonic weapon?

What's behind the strange phenomenon

known as Havana syndrome?

[music]

November 2016, Havana, Cuba.

As the sun sets on the island,

a U.S. diplomat and his wife are unwinding with friends.

SASHA: This couple has just moved to Cuba,

and their names have been kept

anonymous in reports.

But the diplomat and his wife

are living in an upscale development

called El Country Club.

They're having neighbors over for drinks,

and suddenly they hear this sound,

and it fills the air and sounds kind of like cicadas,

only it's a more piercing metallic sound.

LAURENCE: The noise persists through dinner.

JASON HORTON: At the couple's request,

maintenance workers check

the property for insects,

and look for any electrical issues

that could be causing the racket.

But they find nothing.

LAURENCE: The sound lingers for three months,

during which time the couple falls ill.

JASON: He and his wife have been feeling off

ever since shortly after the sounds began--

kind of cloudy with difficulty concentrating.

LAURENCE: After a while, the diplomat

shares his experience with coworkers

at the U.S. embassy.

SASHA: A colleague in his 30s

says that he also heard this high-pitched sound

and started to experience health issues.

And he plays some audio

that he's recorded of the incident.

LAURENCE: It's the same noise

the diplomat's been hearing for months.

Days later, that diplomat and his wife

are examined by doctors in Miami

and diagnosed with concussion-like symptoms--

headache, fatigue, disorientation,

and balance issues.

MICHAEL: More diplomats and others start reporting

exactly the same set of symptoms.

LAURENCE: Over the next two months,

more than two dozen officials in Havana are diagnosed

with the strange condition.

What's even worse, is some of these victims

enter a second phase of the illness

where they have even greater cognitive difficulty

and trouble hearing or seeing.

JOHN: It's really horrible.

These symptoms have just appeared,

and there appears to be no treatment.

You have to wonder, what could cause this

in so many different people?

LAURENCE: To try to learn why, the U.S. government

opens an investigation in January of 2017.

The first group of embassy employees

are thoroughly examined in the United States,

and a report is published

in the Journal of the American Medical Association in 2018.

MICHAEL: Perhaps most seriously and notably,

the study concluded that the patients

had sustained widespread injury to brain networks.

JASON: There is a clear physical change

that has happened to the brains of these patients.

It's visible in the MRIs.

But that change is minor compared to the results

of several neurological tests that target memory,

executive functioning, and spatial orientation.

LAURENCE: According to the study,

these same severe effects would occur

after a devastating car crash or explosion.

But none of these victims have experienced that type of trauma.

At a loss, doctors dub the mysterious illness

Havana syndrome.

Is some strange virus or infection

spreading through the American embassy?

JASON: This, of course, is a huge concern

to multiple government agencies.

For no apparent reason, their staffers

are suddenly dropping like flies.

It's not killing anyone, but it's making them

pretty much unable to function in their jobs

and sometimes in their daily lives.

LAURENCE: In 2018, the U.S. government

brings in the CIA, Defense Department,

State Department, and CDC to further investigate.

At the earliest onset of symptoms,

these victims are hearing a chirping,

a screeching, a clicking, and they're also feeling

a certain pressure in their heads.

They say they're hearing these sounds in their homes

or in their hotel rooms,

and there's a certain directionality to the sensation,

almost like it's coming through a wall

or in a specific part of the room.

LAURENCE: Based on the victims' testimony,

officials believe they have the answer.

Diplomats and CIA officers, or spies,

are the ones who were afflicted.

This is not affecting the general public.

So, the U.S.'s first guess

is that it could be a covert sonic weapon.

JASON: In October 2017,

President Trump holds a news conference

where he calls the incidents, quote,

"a very unusual attack."

He's going public with the idea that this is a weapon.

SASHA: Sound, like anything, can be and has been weaponized.

It's not something we think about

because we can't see it.

But at certain frequencies, it can cause vomiting

and internal distress, and maybe even death.

LAURENCE: It's something the Nazis tried to harness

during World War II.

JOHN: The Nazi regime had a team of scientists

working on wonder weapons

which they claimed would revolutionize the war.

And their chief architect, Albert Speer,

developed one that's called the acoustic cannon.

The idea is to kill or injure someone

by focusing or magnifying soundwaves on a reflective dish.

JASON: At a distance of around 600 to 1,200 feet,

the sound is reported to cause vertigo and nausea

by vibrating structures in the inner ear.

At closer ranges, it could even damage internal organs.

LAURENCE: But this weapon has one serious flaw.

It's huge. The reflector dishes are so big

that it's hard to maneuver, and any damage to the dishes

would render it entirely inoperable.

LAURENCE: While the Nazis' acoustic cannon

was never used in battle,

it paves the way for modern versions.

MICHAEL: In the early 2000s the U.S. developed a weapon

that it called an LRAD-- long-range acoustic device.

These LRADs are capable of projecting

very powerful pulses or beams of sound

up to two miles away.

[alarm wailing] JASON: And if you set it

to emit high-decibel chirping or a beeping sound,

it could also be used as a deterrent.

Nowadays, our military uses LRADs

for everything from crowd control

to repelling pirates from cruise ships.

At a high enough decibel, LRADs can be used as weapons.

They're certainly capable of creating pain,

nausea, imbalance, and even permanent hearing loss.

LAURENCE: It's a promising lead,

but experts say there's one problem

with the sonic weapon theory.

MICHAEL: LRADs are not subtle weapons.

They are definitely very, very loud.

And given that none of the patients in Havana

reported hearing a loud sound,

their reports are not really consistent

with the use of an LRAD.

JASON: So, the next question becomes,

could some foreign power have developed a new sonic weapon,

one that somehow produces the same effects

by primarily using sound outside the range of human hearing?

LAURENCE: There's no evidence found in Cuba.

But in 2019, the Chinese Academy of Sciences

announces a prototype

for the first portable sonic gun.

JOHN: The Chinese claim that they use focus waves

of infrasound.

These waves painfully vibrate the subject's eardrums,

eyes, and brain.

JASON: It may mess with the inner ear,

causing vertigo and imbalance.

Infrasound may also cause nausea, vomiting, bowel spasms,

and potentially affect internal organs like the heart.

In field tests, according to the Chinese team,

it produced extreme discomfort.

JOHN: Of course, this thing had to have been developed

and tested years prior to 2019,

possibly even field tested covertly.

JASON: According to the South China Morning Post,

which first reported the story, this device has been approved

for mass production by the Chinese government.

If that's the case, it's definitely been

in the works for quite a while.

LAURENCE: Still, many doubt this technology

is the source of Havana syndrome.

JASON: In the end, infrasound would be a poor choice

because it spreads in all directions.

It'd be difficult to target specific individuals.

Infrasound can't be easily focused.

It would also affect the user of the weapon,

probably more so than some of the targets,

since they're closer to the source.

And frankly, the effects from an infrasonic weapon

would probably be more annoying than debilitating.

SASHA: In February of 2022,

the Office of the Director of National Intelligence

and the CIA state that there's still a possibility

that this could be a sonic weapon in Havana,

but it would need to be placed extremely close to the target,

meaning against a wall or through a window.

In some of these Havana cases,

the victims were in secure facilities

away from public access.

So, is it possible that this was a sonic weapon?

Sure. But is it probable?

No.

LAURENCE: In 2016,

after more than two dozen American diplomats

develop a mysterious illness called Havana syndrome,

some government officials suspect an ultrasonic weapon.

But computer security engineer Dr. Kevin Fu

has a more surprising theory.

KEVIN FU: My laboratory uses analog signals

to break into computer systems

with lasers, acoustics,

and soundwaves.

LAURENCE: In other words, Dr. Fu specializes

in hacking some of our most sensitive electronics

to identify security flaws and protect against them.

KEVIN: A few of the examples

include creating a homemade radio transmitter

to induce fatal heart rhythms in a defibrillator.

We have used laser pointers over hundreds of feet

to take over voice-controlled assistance.

We have also turned hard drives into listening devices

through some of the mechanisms

on the inside of the spinning discs.

JASON: So, when Dr. Fu first hears about Havana syndrome,

he realizes, "Hey, this sounds kind of like a phenomenon

"I've encountered before.

"My whole job is to glitch out electronics,

and maybe that's what this is-- a glitch."

Dr. Fu believes the Havana syndrome conditions

could have occurred without any massive secret weapon.

This theory states that this could have been caused

by something that was already inside

the embassy staff quarters.

LAURENCE: According to Fu, there's a good chance

the afflicted American officials were under surveillance

while in Cuba, a detail he thinks is key

to solving this puzzle.

KEVIN: I believe that some kind of unintentional accident

with malfunctioning eavesdropping devices

may have caused the sensations that the witnesses reported.

LAURENCE: When Fidel Castro comes to power in 1959,

American diplomats are unwelcome in Havana

for nearly 20 years.

JASON: But in 1977, the United States

reopens a limited diplomatic relationship

to work with Cuba on areas of mutual interest.

From then on, the Cubans keep a pretty close watch

on any American diplomats in their country.

SASHA: As a State Department official, you'd come home,

and maybe you'd see the TV on or the window open,

and you might be thinking, what's happening?

And then you realize that Cuban spies

want you to get this message,

that if you think you're being watched,

you probably are.

JASON: It's almost like a game sometimes.

There are reports of things like an undercover CIA agent

finding his tires punctured,

or maybe his family pet is poisoned.

LAURENCE: Eventually in 2015,

an American embassy reopens in Cuba.

One year later, the first cases of Havana syndrome are reported.

JASON: This is one reason

why the sonic weapon theory never made sense.

Why would the Cuban government initiate a brazen attack

on American officials at the very moment

when they were reopening diplomatic relations?

It just doesn't add up.

JOHN: That doesn't mean the Cubans

quit spying on Americans.

Of course not. Everybody spies on each other,

and we find their devices frequently.

KEVIN: So, when we looked at what the witnesses

reporting about the sensations in Havana,

we started brainstorming about all sorts

of different kinds of conditions

that could make an eavesdropping device

produce the same signals that the witnesses heard.

JASON: If you're going to conduct a spying operation,

you can't just hook up a hidden camera to Wi-Fi.

You've gotta do it in a way that will go completely undetected.

And we know that one way spy devices

secretly transmit information

is through the ultrasonic frequency range.

LAURENCE: Ultrasound technology is most commonly used

in healthcare applications,

motion detectors, and pest repellents.

It's generally considered harmless.

JASON: But Dr. Fu's team has discovered a scenario

where ultrasonic transmitters could become dangerous.

KEVIN: There's an interesting phenomena

when two signals interfere with each other

to create a third tone.

It's called intermodulation distortion.

So, although ultrasound is not audible,

and is designed not to be audible,

if two ultrasonic transmitters come together

and cross paths in the air, they can produce a byproduct

that is quite audible to the human ear.

LAURENCE: Dr. Fu's team is able to replicate this phenomenon,

creating the same metallic chirping sound

recorded by American diplomats.

[metallic screeching]

KEVIN: If you listen to the audio recordings

of some of the incidents and the sound

from our experiments in the laboratory,

we found that the two signals were essentially identical.

LAURENCE: But could these sounds actually make people sick?

According to Dr. Fu, it's possible.

We don't know if these particular sounds caused harm,

because our experiments were all confined to the laboratory,

not involving human subjects.

But we do know that sound can cause harm.

It can cause nausea, internal distress,

it can even cause harm to the human body

at intense enough frequencies.

LAURENCE: But not everyone's convinced.

It doesn't make any sense as an intentional act,

at the very least.

If you're spying on somebody,

you do not want your devices

that you're using for surveillance

to drive away the people that you're trying to spy on,

which is exactly what happened.

The reason why Dr. Fu and many others

have researched this is because there's no answers

to what is causing the Havana syndrome.

The U.S. government hasn't been able to figure it out.

At least Dr. Fu has replicated the noise,

and that's more than most people have accomplished.

Part of the scientific process is about exploring

many different hypotheses,

some of which may turn out to be incorrect or less likely.

But we hope that the research done in my laboratory

is helping us come closer as a community to a conclusion

to solve this mystery.

LAURENCE: Initially, the mysterious Havana syndrome

only impacts U.S. diplomats in Cuba.

But by March of 2018, diplomats at another embassy

in Havana fall victim.

JASON: It starts happening to the Canadian embassy staff.

This is very strange

because the Canadian embassy

is about three miles away

from the U.S. embassy,

so it's not like they're adjacent or anything.

MICHAEL: Canadian diplomats and their families

start reporting exactly the same

kinds of symptoms

U.S. embassy staff had reported.

Disorientation, nausea, dizziness.

Ultimately, 40 Canadian diplomats fall ill,

and so the Canadian government ends up pulling its diplomats

out of Cuba.

LAURENCE: By 2019, Canada's workforce in Havana

is reduced by half.

This illness, whatever it is,

is severely limiting their ability

to conduct diplomatic relations in Cuba.

LAURENCE: That same year, Canadian officials

launch their own investigation.

At this point, the Americans are probably glad

to have the help.

We've got no clear motive,

no clear means, and no good suspects.

MICHAEL: It's causing a lot of confusion, frustration,

and really starting to feel kinda like

they're in some sort of bad spy thriller.

LAURENCE: Among the Canadian researchers

is Dr. Alon Friedman,

who works at a highly regarded brain research center

in Nova Scotia.

Dr. Friedman is a neuroscientist

who studies the blood-brain barrier,

and in particular, the chemicals that can cross that barrier,

which typically protects your brain

from most chemical attacks.

JOHN: Although some researchers have looked at the causes

being maybe sonic or physical,

Dr. Friedman is looking to see

if it may be a chemical characteristic.

MICHAEL: While the blood-brain barrier

does protect against a lot of chemicals,

it turns out that the number of chemicals

that can cross that blood-brain barrier,

still very large.

And so, Dr. Friedman wants to look at every possibility.

It's not even really finding a needle in a haystack.

It's looking at a haystack and not knowing

if there are any needles inside.

LAURENCE: Dr. Friedman conducts brain scans and MRIs

on 23 Canadian diplomats and their families.

Initial evaluations confirm the Canadians

have damaged brain tissue just like the Americans.

In addition, Dr. Friedman

conducted a range of blood tests,

as well as something called mass spectrometry.

Mass spectrometry is a technique

that creates a fingerprint for a chemical,

allowing you to tell exactly what is there

and how it's comprised.

Specifically, he was on a search for neurotoxins,

because all the symptoms are consistent

with some sort of damage or effect on the nervous system.

JASON: Turns out, they find neurotoxins.

They find them in every single symptomatic patient

that they test.

JOHN: Everyone has some toxins in their body,

but based on this study,

it appears that the Havana syndrome

could have been caused by a chemical weapon.

MICHAEL: The pattern of brain injuries

in the patients from Havana

are consistent with regular low-dose exposure

to a class of neurotoxins called cholinesterase inhibitors.

These chemicals have been used

in some of the most deadly chemical weapons attacks

on the planet.

Now, cholinesterase inhibitors, as the name suggests,

inhibit cholinesterase from working.

This chemical is crucial for the communication

between the brain and the muscles.

If your brain cells cannot talk to each other,

then you have problems thinking.

MICHAEL: Some cholinesterase inhibitors have been weaponized.

One famous example is sarin.

Originally developed by Hitler's Nazi Germany,

it was so devastating that even Hitler was scared to use it.

LAURENCE: Another variant of this chemical

is called Novichok.

This was a chemical that was found in the bloodstream

of Russian opposition leader Alexei Navalny,

who was poisoned in 2020.

MICHAEL: Obviously, cholinesterase inhibitors

can be very dangerous, even deadly.

And so, Dr. Friedman wants to find out

exactly what kind of cholinesterase inhibitor

is affecting these patients.

LAURENCE: After further testing, Dr. Friedman's team

is able to identify the chemical.

It isn't as nasty as sarin or Novichok.

It is something else called temephos.

MICHAEL: Temephos is not particularly lethal,

but regular exposure can cause symptoms

such as dizziness, disorientation,

sensitivity to sounds-- symptoms that align

with what was reported in Havana syndrome.

JOHN: When the Havana syndrome first hits the news,

a lot of people are saying this sounds a lot like a weapon.

LAURENCE: But there's also a less sinister possibility.

Temephos is used widely throughout the world

as an agent to control mosquitos.

It attacks the nervous system of the larvae,

preventing them from turning into adults,

and therefore helping to stop the spread

of mosquito-borne illness.

It is in a sense a pesticide.

Dr. Friedman concludes that these diplomats

and their families have been exposed to pesticides.

LAURENCE: Could high levels of pesticide

actually be responsible?

In March of 2015, Zika is officially detected in Brazil,

and by 2016, the World Health Organization

has declared it a public health emergency.

LAURENCE: The Zika virus is transmitted by mosquito bites.

JASON: Countries are spraying for mosquitoes like crazy.

Tropical and semitropical places like Cuba

are using vast quantities of temephos.

LAURENCE: And the timing seems to fit.

JOHN: Cuba reports its first outbreak

of the Zika virus in March of 2016.

The first American diplomats report symptoms

of the Havana syndrome about six months later.

MICHAEL: Canadian records confirm that in 2017,

the Canadian embassy and its grounds

increased the use of temephos pesticides,

which roughly coincides with symptoms

in their embassy workers.

JOHN: In fact, the EPA has actually outlawed temephos

as a residential pesticide

because of its neurological effects.

LAURENCE: But not everyone's convinced

Friedman's solved the mystery.

JASON: Temephos was being used all over the place

throughout the Americas,

not just at diplomatic residences.

It was in Cuban government offices,

Cuban homes, and dozens of other places

where Havana syndrome didn't occur.

What about Brazil? What about Colombia?

If temephos caused this illness,

you'd have seen it affect a much larger group worldwide.

LAURENCE: Regardless, Dr. Friedman still believes

a chemical could be the cause.

MICHAEL: This doesn't mean that it couldn't be

a neurological agent of some kind at play.

Friedman couldn't test for everything.

He tested for a handful of likely candidates,

and it's possible that there was something else at play

that he didn't test for.

In the end, we can't rule out that the Havana syndrome

may have been caused by chemical exposure.

JASON: Is there another chemical weapon out there

that we don't yet know about?

Hopefully not, but maybe.

As growing fears about the mysterious Havana syndrome

threaten relations between the U.S. and Cuba,

the Cuban government launches its own investigation.

In 2018, Cuba's officials announce their findings,

and identify a surprising new culprit.

JASON: From very early on, the United States has believed

that Cuba is behind Havana syndrome somehow.

I mean, you give it that name,

the president goes on live television

to blame the Cubans,

this is a very bad look for them.

JOHN: Some in the White House

are actually calling this an act of war,

so the Cubans are very anxious

to clear their name.

SASHA: The Cuban government interviews about 300 neighbors

of these diplomats.

They say that they've gone to the living quarters

of embassy staffers,

that they've analyzed air and oil samples,

and that they've conducted dozens of medical examinations

to see if people in the surrounding area

were afflicted, and they say they find nothing.

JASON: The Cubans are saying

there's simply no known form of energy

that can selectively damage the brain

the way the doctors describe.

They're even doubtful that there's a syndrome at all.

LAURENCE: Instead, they offer an alternative explanation

for both the sounds and the symptoms.

JOHN: The Cuban government in their report

theorize that this was not caused by sonic weapons,

and the chirping noise heard by everyone was crickets.

The rest of the symptoms, the Cuban government says,

could be caused by stress.

JASON: After all the hours investigating,

evacuating diplomats,

conducting extensive medical tests,

to suggest that maybe people were just worn down

by the sound of crickets?

That feels like an insult.

LAURENCE: Two biologists, UC Berkeley's Alexander Stubbs

and the University of Lincoln's Fernando Montealegre-Zapata,

research Cuba's claim.

To them, that metallic chirping noise

recorded in Havana sounds vaguely familiar.

KEVIN: These biologists had a massive database

of the sounds of different kinds of insects,

their mating calls.

And what the biologists found

is that the sounds

that were recorded in Havana

match precisely that of one particular kind of insect,

the Indies cricket.

And moreover, this particular Indies cricket

is resident in Cuba.

LAURENCE: For confirmation,

they use state-of-the-art audio technology.

Forensic audio analysis can be incredibly specific these days.

Soundwave patterns can be kind of like fingerprints.

They can even be used to convict killers.

KEVIN: So, what's interesting is that when you apply

some of these acoustic forensic techniques

to what was recorded in Cuba,

it's an exact match of the cricket mating call.

SASHA: Obviously, crickets aren't as menacing

as a sonic weapon or a deadly neurotoxin,

but this isn't your garden variety cricket.

The Indies cricket can chirp at 100 decibels,

the same volume as a subway train.

MICHAEL: You can imagine that if you had a couple

in your residence, that could be a really rough night,

especially if you're not habituated to those sounds.

If you're from another country

and this is the first time you've ever heard it,

that could be extremely disruptive.

LAURENCE: According to the Cuban report,

the crickets may be magnifying stress

that the diplomats are already experiencing.

JOHN: The Havana syndrome has some classic telltale signs

of psychogenic illnesses.

There are studies that show that people

who have been exposed to long-term stress

have similar brain scans as the Havana victims.

JASON: That stress might be self-perpetuating.

After the news of a possible weapon

hits the media, the diplomats are put on alert.

They're told that someone could be watching them at home.

They're told not to sleep or to stand near their windows,

and to report any strange symptoms.

They're afraid for their families.

They can never feel safe.

LAURENCE: But those suffering from Havana syndrome

strongly disagree.

Several people got sick before there was an alert,

before it reached headlines and people went into panic mode.

And the first four cases were CIA officers.

These are people who are trained

to deal with massive amounts of stress.

LAURENCE: With opinions split over the cricket theory,

the U.S. government calls in an elite scientific team

to conduct its own analysis.

JOHN: The federal government has a semi-secret advisory board

known as JASON.

It was originally called Project Sunrise,

and was later changed to the name JASON

from Greek mythology.

It was formed in the aftermath

of the Soviet Sputnik launch in 1960.

SASHA: JASON attracts the nation's most elite scientists

to advise on defense matters,

kind of like what we saw in World War II

with the Manhattan Project when Einstein and Oppenheimer

were researching nuclear energy and weapons.

JASON: Today, there are between 30 and 60

of our country's best scientists involved in JASON,

and they're only activated

when there's a particularly difficult task at hand.

SASHA: And at this point, the U.S. government

sees Havana syndrome as such a difficult matter,

that then they turn to JASON.

JASON: Through a Freedom of Information Act request,

JASON's top-secret 2018 report is released to the public.

And while much of it is redacted,

the JASON scientists concur that the noises

on the Havana recordings are crickets.

LAURENCE: While they agree on the source of the sound,

they don't agree on the source of the illness.

The report goes on to say, quote,

"It cannot be ruled out that the perceived sounds,

"while not harmful, are introduced

"by an adversary as deception

"so as to mask an entirely unrelated mode

of causing illness in diplomatic personnel."

Basically, they're saying these crickets

could be a distraction to hide another form of attack.

And suddenly, the Cubans blaming the crickets

seems really convenient.

JASON: Maybe the Cubans are involved, maybe not.

Either way, once again, we're left with no idea

what's making our people sick.

LAURENCE: December 2017, Moscow, Russia.

CIA operative Marc Polymeropoulos

is asleep in his hotel room

when he is awakened by a strange sound.

MARC: In the middle of the night, I woke up

and the room was spinning.

I had a terrible case of vertigo.

I couldn't get up. I was falling over.

I had tinnitus, which is ringing in my ears.

I had a splitting headache in the back of my head.

And overall, there was just this incredible feeling

of being disoriented.

I was-- I was frankly terrified.

LAURENCE: At the time, Marc believes he has a bad case

of food poisoning.

I had been in Iraq and Afghanistan,

been shot at a whole bunch of times,

but I was flat-out scared.

LAURENCE: A veteran operative,

Marc's been posted on covert missions

all over the world.

MARC: I was the Deputy Chief of Operations

of the Europe and Eurasia Missions Center

that entailed oversight over all CIA's clandestine operations

from Dublin, Ireland,

to the farthest regions of Russia,

which encompasses 11 time zones.

So, my position at the time was the equivalent

of a three-star general.

It was a routine trip where I'm talking

to my counterparts in the Russian Security Services.

LAURENCE: Marc's symptoms subside for a few days.

MARC: I was eating at a very fancy restaurant in Moscow,

and the symptoms came back, particularly the vertigo.

I remember clearly that the room started spinning again.

The headaches came back even more severe,

the tinnitus, the ringing in my ears.

And I had to get back to my room,

and in effect, for the last couple days of my trip,

I didn't really do much.

The vertigo was so disorienting,

and I kind of crawled up the stairs of the airplane

to finally make my way back to the United States,

hoping that, you know, these symptoms would get better.

LAURENCE: As time goes by, however,

his symptoms only get worse.

I proceeded to go to multiple doctors,

and these included allergists, infectious disease specialists,

multiple neurologists, pain doctors.

And for months and months, they could find no way

to alleviate my symptoms.

But still, it was a mystery to them what occurred.

LAURENCE: One year later, news breaks of a similar illness

affecting diplomats in Havana.

MARC: I still was having these symptoms,

I still was feeling incredibly ill.

When I heard about what had happened to officers

at the U.S. embassy in Havana,

I had actually at the time

thought I could have experienced the same thing.

LAURENCE: Convinced there's a connection,

Marc takes his complaint

to the CIA's Office of Medical Services.

And I went and I asked CIA doctors there,

take a look at me, but in about a 10-minute quick interview

and exam, they thought I did not look like the U.S. officials

who were afflicted by Havana syndrome.

But really, what was interesting and pretty alarming

is that officers that I knew would stop by my office

and they'd say, "Hey, something happened to me."

Their symptoms were very similar.

They had an event occur, usually in a hotel room.

It was the same things, such as vertigo,

splitting headaches.

And like myself, they were all involved

in Russian operations.

Unfortunately, there still was a lot of resistance

from inside the Office of Medical Services.

But really in that timeframe,

I started suffering from brain fog

and had a bout of several weeks

where I lost my long-distance vision.

Ultimately, the result of all this,

I couldn't perform my duties.

And in mid-2019, I made the decision

that I would retire.

LAURENCE: Polymeropoulos believes he may be one

of the first to experience Havana syndrome

outside of Cuba.

JASON: In June 2018, nearly a dozen diplomats

are evacuated from Guangzhou, China,

with similar symptoms.

Since then, even more possible cases

have popped up in Georgia, Poland, Taiwan,

Australia, and the list goes on--

Colombia, Kyrgyzstan,

Uzbekistan, and Austria.

LAURENCE: Cases have even been reported on American soil.

MICHAEL: At least two cases of Havana syndrome

have been reported in the United States,

including one on the south side of the White House.

We don't know if these cases are linked,

we don't have any idea of the cause,

but some doctors have dubbed it "the immaculate concussion."

SASHA: Now that Havana syndrome is happening outside of Cuba,

it opens up a staggering array of possibilities.

It doesn't have to be caused

by something developed in Cuba,

but it does have to be something

small enough to be smuggled into Cuba

and into other countries.

JASON: And I'd say that if these many attacks

in various countries are connected,

that pretty much rules out the accidental theories

like pesticides

or poorly-calibrated listening devices.

SASHA: It seems more likely that this is originating

from a country with more influence than Cuba.

I don't think they have the capability

to pull off so many incidents

in so many countries across the world.

MICHAEL: So, the question becomes,

is there a weapon that could possibly fit the bill?

Something small, portable, and in the hands of a government

connected enough to global politics

to get an advantage from causing that kind of panic?

LAURENCE: When cases of Havana syndrome

start surfacing worldwide

in 2018, U.S. officials

can't find a definitive cause.

But former spies like Marc Polymeropoulos

believe they know the source.

Obviously, I wasn't there

in Cuba, but when talking

to the victims, it is very similar

with what I felt at that hotel in Moscow in 2017.

LAURENCE: Polymeropoulos thinks he's the victim

of a unique deadly weapon.

Of course, you've heard the word "microwave" before.

Most of us have microwave ovens

to heat food.

The difference with a microwave weapon

is not the fundamental kinds of waves it's producing.

They're still microwaves.

It's that they're producing them at much, much higher energy.

In other words, you've supersized the system.

KEVIN: There's a small device on the inside of the microwave

that emits tiny, tiny radiofrequency signals.

And these tiny radiofrequency signals heats up molecules.

In the case of a microwave weapon,

you're not simply heating up

a cup of coffee,

but you're actually heating up human tissue.

JOHN: A high-powered microwave weapon

may explain the symptoms--

the nausea, the vertigo,

the headaches, even the reported sounds.

It can really do a number

on the electro-neurological functions of the brain.

MICHAEL: Unlike a sonic weapon,

which are very difficult to focus into a narrow area,

microwaves are very easy to direct.

JOHN: You point a microwave one way,

and that's the way it goes.

It will not hit the person who's firing it

or impact the surrounding neighborhood.

KEVIN: Microwave technology has been rapidly advancing recently.

Is it possible that a weapon

has been developed that can

target a single individual,

fit in a suitcase,

and be deployed from a few hundred yards away?

Well, the U.S. has already created something pretty close.

LAURENCE: In 2004, the U.S. Marine Corps

commissions the development

of a microwave weapon code-named MEDUSA.

SASHA: MEDUSA, or Mob Excess Deterrent Using Silent Audio,

this was basically a nonlethal microwave ray gun

that could be channeled at people,

and it could potentially incapacitate them.

JOHN: These microwaves can stimulate the parts

of the inner ear and mimic an actual audio signal.

This gets interpreted by the brain as sound.

This is what's called the Frey effect.

MICHAEL: MEDUSA can make you feel like you're hearing

different kinds of sounds, even recognizable sounds

like voices inside your head.

This could be the source of the sounds

reported by those experiencing Havana syndrome.

JOHN: Although the U.S. has been toying with these weapons

for about 20 years, we know of another country

that has been using them for longer.

The Russians deployed a microwave weapon

against the U.S. during the Cold War.

LAURENCE: Starting in 1953 and continuing until 1976,

Soviet authorities aim a near-constant microwave beam

at the U.S. embassy in Moscow.

JOHN: Their goal was to interfere with communications

inside the U.S. embassy.

Intelligence officials called it the Moscow Signal.

Although they detected it early on during routine checks,

American officials kept it quiet.

It's only when the American ambassador to Russia,

Walter Stoessel, threatens to resign in 1975,

that members of his staff are informed.

SASHA: The embassy officials get tested,

and many of them have elevated white blood cell counts.

And Walter Stoessel, like two of three ambassadors before him,

dies of cancer.

And Stoessel had a severe form of leukemia

that reportedly caused his eyes to bleed.

JOHN: Over 100 employees file for damages

against the U.S. for exposure to the Moscow Signal,

but a State Department study

found there was no convincing evidence

of adverse health effects.

SASHA: Now, the lawsuits are dropped,

and it basically fades from public view

until these afflictions, these mysterious cases

arise in Havana.

LAURENCE: Could Havana syndrome be the next phase

of a decades-old covert operation?

In my view, what happened to, you know, my colleagues

at the U.S. embassy in Havana, Cuba,

and what's happened to myself and some others

is absolutely a continuation of what the Soviets

were doing to us at the U.S. embassy in Moscow.

That said, you know, we do have another adversaries.

We have the Chinese, we have the Iranians.

And it is entirely possible

that more than one country is doing it.

Polymeropoulos isn't the only spy who believes this.

There's actually another account that is more shocking than his.

LAURENCE: In 1996, NSA Officer Mike Beck

suffers sudden severe fatigue while on assignment

in a classified foreign country.

JASON: This predates Polymeropoulos

and the Havana syndrome cases by about 20 years,

but Beck and his attorney believe it's all related.

JOHN: Beck cannot reveal what country he was in,

but his attorney stated it was a hostile nation

that was not China or Cuba.

SASHA: Beck's job was to go to a diplomatic building

and make sure that it wasn't being bugged.

And while there with his partner,

he does find a suspicious device.

JOHN: The very next day, they both get symptoms

that are now associated with the Havana syndrome.

LAURENCE: Beck fully recovers, but 10 years later,

both he and his partner develop the same form

of Parkinson's disease.

SASHA: Beck is certain this isn't a coincidence,

so he files a claim for workers' compensation,

something that people do every day.

Only, Beck's employer is the NSA,

and his claim relies on top-secret information.

JASON: Incredibly, as part of his claim,

the NSA actually provides Beck with a declassified document

which may finally prove what happened to him.

SASHA: The memo Beck was given states,

"there is intelligence information from 2012

"associating the hostile country

"to which Mr. Beck traveled in the late 1990s

"with a high-powered microwave system weapon

"that may have the ability to weaken, intimidate,

or kill an enemy over time, and without leaving evidence."

It goes on to say this:

"...intelligence information indicated this weapon

"is designed to bathe a target's living quarters in microwaves,

"causing numerous physical effects,

including a damaged nervous system."

Is this proof of the Havana syndrome?

Well, no.

But it does prove what happened to Beck

may be the same thing that happened in Havana.

But at the very least, we now have confirmation

that such a weapon exists.

And if we ever find evidence that that weapon is in Cuba

or some other country, it may explain everything.

Meanwhile, though we can't say why it's happening,

we know this illness is real.

And on October 8th, 2021, Congress passes the Havana Act

to compensate government officials

who've experienced brain injuries

as a result of Havana syndrome.

So far, 1,000 people

have come forward

claiming injuries related to

the so-called Havana syndrome.

And while the investigation remains active,

no concrete evidence has been found

that a U.S. adversary is responsible.

I'm Laurence Fishburne.

Thank you for watching

"History's Greatest Mysteries."