Original subtitles

It's the case that has gripped Argentina.

Alberto Nisman was a special prosecutor investigating

the country's worst terror attack.

Hours before he was due to testify in Congress, he was found dead

at his luxury flat.

Suicide or murder?

After weeks without answers, come here to try to piece together

Alberto Nisman's final hours and ask the question who may have

wanted him dead.

His ex-wife spoke to us in an exclusive interview.

And we question the man who may have been the last to see him alive.

Did you know you had a gun?

We look at the evidence and ask, who killed Alberto Nisman?

The story begins 21 years ago on July the 18th, 1994.

A massive bomb destroyed the Amia, a Jewish community centre in

Buenos Aires, killing 85 people.

This previously unseen footage, show now for the first time,

shows the ensuing chaos.

Rescuers ask, "Is anyone there?

Is she alive?"

As a young reporter, I came to Buenos Aires to cover

the aftermath of the 1994 attack.

At that time, everyone I talked to was in shock.

How could this happen here, in Argentina?

Much of the evidence was lost or contaminated, either deliberately

or through incompetence.

No one has ever been convicted for the Amai bombing.

Alberto Nisman, a 51-year-old prosecutor, had spent almost two

decades investigating who was behind the Amai attack, trying to crack the

case that no-one else could solve.

He was a meticulous and driven man, but he would never finish his task.

In an exclusive interview, Nisman's ex-wife described how he

In an exclusive interview, Nisman's ex-wife described how he

told their eldest daughter that the work he was doing was dangerous,

but that he had no choice.

At this luxury apartment complex in Buenos Aires, Alberto Nisman was

At this luxury apartment complex in Buenos Aires, Alberto Nisman was

preparing to deliver a damning report, accusing the Argentine

government of being involved in covering up the worst terror

attack in the country's history.

But just hours before he was due to testify, Nisman was found dead, here

in his 13th floor apartment, with a single gunshot wound to the head.

Our investigation reveals new details about Nisman's final hours.

We examine evidence from the crime scene and talk to key figures.

Did the prosecutor kill himself?

If not, was he murdered by someone close to him?

Or could he have been the victim of a power struggle in Argentina's

notorious secret services?

How and why Alberto Nisman died is an intriguing but complex story.

And one which may not end, even once the official report is released.

While working on the Amai case, in recent months, Nisman had embarked

on a parallel inquiry which made him enemies at the highest level.

His body was discovered hours before he was due to present this

second report to Congress, in which he accused

the government of plotting with Iran to cover up the Amai government.

Nisman trusted few people and often worked from his flat.

It was here, on the 18th of January this year, that he was found dead.

Apparently alone and with a handgun next to his body, many senior

figures in Argentina immediately assumed Nisman had killed himself.

Even President Fernandez de Kirchner speculated on her Facebook page what

may have made him take his own life.

But Sandra Arroyo Salgado, Nisman's former partner,

disputed the official version of events from the start.

I knew it might break me, Nisman had said, just days

before he died, admitting his accusations against the government

would make him a marked man.

At the time of his death, Sandra Arroyo Salgado was travelling

abroad and, although they were separated, she returned home to

the glare of the media.

Let the investigation take its course, she said then.

But appalled by the rapid speed of the autopsy and

the failure to preserve evidence at the scene, Arroyo Salgado, a judge

herself, began her own inquiries.

Official images, obtained by the BBC, pointed to a shocking

lapse of protocol and procedure at the flat where Nisman died.

Several people, walking all over the scene

and evidence improperly collected.

The woman now in charge of the official investigation into Nisman's

death denied her office mishandled those initial hours at the scene.

A public feud between two of Argentina's highest profile

female legal figures over key facts has captivated the country.

It is believed that Viviana Fein's official investigation will rule

that Nisman killed himself.

However, Sandra Arroyo Salgado's investigators say

the evidence suggests otherwise.

Including the way that Nisman's body was found after his death.

Nisman was lying on his back in the bathroom, with the gun that

killed him behind his left shoulder even though he was shot in

the rear, right side of the head.

One of Argentina's leading crime reporters says that points more

towards a possible assassination, a theory he says is supported

by criminologists from Interpol.

The weapon that killed Nisman, a .22

calibre Bersa handgun, belonged to a 38-year-old computer

specialist who worked closely with the prosecutor - Diego Lagomarsino.

In the chaotic press conference after the body was found,

Lagomarsino denied being part of a conspiracy to kill his boss.

Later, he told me his version of events, that Nisman asked him

for the gun because he didn't trust his police bodyguards.

Did he know you had a gun?

Did you feel you had no choice, you had to give him the gun?

You seem quite angry.

Is that a fair reflection?

Lagomarsino says he took the gun to Nisman's apartment on

the Saturday evening and then left.

But Sandra Arroyo Salgado says her investigators concluded that Nisman

actually died on the same Saturday night.

It all comes down to what happened in those critical 24 hours

between when Lagomarsino says he gave Nisman the gun, and when the

body was found on the Sunday night.

One important key to that period is the apparent lack

of communication from Nisman after Saturday evening, rare for

such a busy and work-obsessed man.

What you are saying is if Alberto had been alive on Sunday morning,

he would have been active, he would have been phoning people, he would

have been contacting people.

Instead, we asked to believe he was silent all day Sunday?

The vast majority of Argentines share Arroyo Salgado's suspicion

and her scepticism that the case is being handled neither

impartially nor independently.

Exactly one month after Nisman's body was found, hundreds

of thousands marched in torrential rain across the capital protesting

against impunity - the feeling that, yet again, another high-profile

crime would inevitably go unsolved because of judicial incompetence

and political interference.

Alberto Nisman was laid to rest in a quiet corner of the

Tablada Cemetery.

His grave, piled high with stones of remembrance.

Our investigation revealed that Nisman was walking a fine line in

his work on the Amia case and his accusations against the government.

A number of people could have wanted him dead and he had received

many threats against his life.

Only a few metres away from Nisman was not grave lie those who were

killed in the Amia bombing.

They were victims of an attack on one of the largest Jewish

communities outside Israel and Alberto Nisman believed

their memories were being betrayed by the Argentine government.

21 years later, a huge amount of evidence has been

amassed, interviews, witness statements and wiretaps.

Alberto Nisman spent 17 years working on this case.

It was his life's work.

500,000 files and audio tapes, gathering dust

in a government warehouse.

"Escuchas" - the Spanish word for wiretaps.

This was among the evidence that in 2006 lead Nisman to formally

accuse Iran and its ally, Hezbollah, of being behind the Amia attack.

So when Argentina signed a deal with Iran in 2013,

establishing a truth commission, ostensibly to start a joint

investigation into the bombing, Nisman could not contain his anger.

He felt betrayed and accused President Fernandez de Kirchner

of acting unconstitutionally and illegally interfering

in the judicial process.

It was then, in a move that may have cost him his life, that he began

the secret, parallel investigation, alleging the government was part

of an elaborate cover-up.

Argentina's combative leader was having love it.

In the weeks after Nisman's death, she showed little public simply

for the dead prosecutor's family and was accused of rallying her own

supporters to exacerbate the already deep divisions in Argentine society.

She dismissed Nisman's conclusions that she and her Foreign Minister

Hector Timerman had illegally cooked up the deal with Iran to

benefit Argentina financially.

Foreign Minister Timerman who, like Nisman, is Jewish,

told me it was inconceivable that he would betray the memories of those

who died in the Amia bombing.

Although Nisman had even drafted an order of arrest for Timerman and the

President, the Foreign Minister said Nisman's allegations of a cover-up

were baseless and the idea of arresting the President has already

been rejected by the courts.

Do you say that in this case you have done nothing wrong?

You all the President?

Nothing, nothing at all, on the contrary.

We did more than any other government in order to find out who

committed the terrible crime against the Jewish centre.

More than any other government.

We know from leaked documents that Nisman was a regular visitor to

the US Embassy in Buenos Aires.

He saw secret intelligence briefings that probably influenced his

investigation into the Amia bombing.

He is also believed to have close links with the Israeli Mossad.

After Nisman died, Hector Timerman sent open letters to Washington

and Israel, warning them to back off the internal affairs of Argentina.

I think that there are countries whose intelligence services

operate in third countries without authorisation of those countries.

What I am saying in my letter is just telling them that they are

doing that, they should stop.

Is this all coincidental?

Are you sending me is warning letters to the Americans

and Israelis because of what we have learned from the Nisman case?

That is something I prefer not to answer.

If I can push you slightly differently,

do you have evidence that there were foreign agencies at work?

We don't send letters without evidence.

But foreign spies were not the only shadowy figures in Nisman's world.

He also moved in dangerous circles much closer to home.

From its headquarters overlooking the presidential palace,

some say this is the real seat of power, Argentina's Internal

Intelligence Agency.

For decades, its operations director was Antonio "Jaime" Stiusso,

a man so elusive that only one known picture of him exists.

He worked closely with Alberto Nisman on the Amia case,

feeding him wiretaps and other sensitive information.

After Stiusso was suddenly sacked by the President in December,

a possible theory was that Nisman could have been the victim

of a power struggle between the government

and an intelligence service not used to being challenged.

The only person who can request a change to this...

Argentine judge and international war crimes prosecutor Luis Moreno

Ocampo says the power still wielded by military era spies has compromise

the independence of the judicial system where Nisman worked.

In the 70s and 80s, our intelligence system was part

of the massive atrocities committed by the dictatorship.

This is over.

We stopped it and and we prosecuted the junta leader for that.

The Nisman case exposed that the democratic government did not

change the functioning of the intelligence system.

Yes, they are no more committing massive atrocities.

But the intelligence system is used to

manage money for political purposes, to spy on opposition members, and to

control judges and prosecutors that want to investigate the government.

So, that is what we have here.

The Nisman case exposed that.

Nisman was using the intelligence services,

but he was also being used by them.

Could this be the reason that he died?

In a city full of secrets and suspicions, the one person that

got really close to the prosecutor, and allegedly gave him the gun, was

IT specialist Diego Lagomarsino.

But was he also an intelligence agent and, as some have alleged, did

he have a role in Nisman's death?

No, Lagomarsino told me, emphatically.

His job was merely to look after the prosecutor's computer needs.

Alleging that Nisman was fond of a highlife, government ministers and

insiders have gone to extraordinary lengths to is the prosecutor died to

sully his character, accusing him of being a womaniser and even

misappropriating from his office.

The smear campaign against a man who valued reputation

and image, and the obvious political context, leaves Nisman's family

feeling like the official investigation into his death is

being deliberately manipulated.

Did you feel there was an attempt by the state, by the authorities, to

control things, from the very start, to leave you, as a family, outside?

Alberto Nisman never got here to Congress to deliver

his controversial report.

It was criticised by many, but those who knew Nisman say he was convinced

by the veracity of his work and was certainly not suicidal.

But he is dead, and by the end of the year Argentina

will have elected a new President and a different Congress.

For the families of Alberto Nisman and the victims of the Amia bombing,

hope is fading with time.

To come back here two decades after the Amia bombing and see such

little progress is galling.

And it suggests that Argentina's transformation

into a fully functioning democracy is not yet complete.

That the system has also failed a man who dedicated

his life to investigating the Amia bombing is also a tragedy.

The official investigation has still to rule on the cause of death,

but few people here now believe this was a case of suicide.

A complete loss of faith in that system means we may never

know who killed Alberto Nisman.