But that same technology it also letting citizens watch the state.

We know that Facebook is spying on us,

we know that Google is spying on us.

But those mediums can also become mediums of counter forensics.

We are watching the watchers.

We are reversing the forensic gaze.

The rise of social media and the proliferation of smart phones has made it easier than ever for people to consume news.

But not all this information is true.

Some governments use these platforms to disseminate propaganda, and monitor citizens behavior.

Now this technology has also helped to turn the tables on the powerful.

Every comment, every photo, every video, is a clue to ultimately getting at the truth.

The big challenge is to figure out how we find all those clues and ultimately use them almost like pieces in a puzzle.

Alexa Koenig is a law professor and investigator.

She gathers evidence from multiple digital sources, to investigate some of the biggest human rights abuses in the 21st century.

So many war crime cases fall apart at fairly early stages of prosecution.

One of the big challenges is that prosecutors are over-relying on witness testimony.

And of course with time and trauma, a testimony becomes fallible.

Miss Koenig's team has helped investigate atrocities in Myanmar, Syria and Yemen.

Unlike traditional investigators, her team uses open source evidence.

So we brought together people doing big data analytics,

satellite imagery, remote sensing, people who were

thinking through how cellphones could be harnessed and support the stories of survivors.

The team has investigated atrocities in Myanmar in 2017.

The evidence proved that the army had used Facebook's

wide reach in the country to post false information

inciting hatred against the Rohingya Muslim minority.

This type of evidence is gaining traction and is being used by the international criminal courts.

Open source information that you can find online

is increasingly being used by groups like the United Nations

and by the International Criminal Court.

It released its first ever arrest warrant based on

information pulled from social media in Libya.

Meanwhile, Bellingcat, a group

of open source experts, has been investigating the poisoning

of a former Russian spy, Sergei Skripal

and his daughter in 2018.

They have made some striking discoveries.

Bellingcat disclosed the names of three Russian agents who they allege were involved in the attack,

strengthening the suspicion that it was sanctioned by the Russian State.

In response, the Russian authorities claimed that

the men were tourists, but Bellingcat proved that

the three men were high ranking members of the Russian army.

One of the agents had even been honored by President Vladimir Putin personally.

What Bellingcat did was they began to comb social media

and find the profiles of the people

who were thought to have been involved,

that Russia was saying were just tourists,

and ultimately establish the true identities

in a way that really shocked the world.

Bellingcat cross referenced photo and video

evidence released by the British and Russian authorities,

with social media to find the men's true identities.

This is not the first time the state has been accused of trying to cover its tracks.

Governments are trying to release false information about things that have taken place.

We need to not only establish what has taken place,

but to deconstruct government statements that are misleading.

Eyal Weizman is an open source expert based in the UK.

The most recent incident which he has investigated

raises questions about the death of Palestinians during an Israeli airstrike.

In 2018, these two boys were sitting on a roof top.

They were killed moments after taking this selfie.

The Israeli armed forces said they fired

non-lethal warning shots to clear the area of civilians.

They call this tactic 'knocking on the roof.

Hours later, the Israeli army released a video which appears to show four warning shots, followed by the main strike.

But forensic architecture stitched together mobile phone and CCTV footage disputing their claim.

They allege the Israeli army did not release a video of the first shots which killed the boys.

Instead, it substituted it with a video of the third strike from another angle.

The Israeli army denied distorting evidence.

Investigating state operations isn't cheap.

It takes time and resources.

One big question is always where's the money coming from to do this kind of work.

There are some individual donors who really believe in the power of technology for social good.

And increasingly we still do see some states that are

really interested in the power and possibility

of pulling together information.

The evidence and practices of groups

such as Bellingcat and forensic architecture are open to everyone.

This evidence is traceable and verifiable.

But lawmakers must approach it with caution.

The use of this evidence in court is in its infancy and raises several problems.

I think so few judges today are trained in ways to really

interrogate what makes for a good digital investigation,

that there's really a two-fold risk.

The first risk is that they're going to look at this very

slick sexy package and they're gonna find it so convincing,

that they ultimately don't interrogate

the underlying bits of information.

The second risk, of course, is that they're just going

to look at this and say I have no way to understand

the original sources of this information,

and so they dismiss it out of hand.

It is increasingly difficult

to separate fact from fiction.

But crowdsource investigations offer a new way.

Giving a voice to victims and holding the powerful to account.