A shadowy website spent hundreds of thousands of dollars on political adverts on Facebook and other networks. But the people behind “Mainstream Network” have managed to remain entirely anonymous. No-one knows who runs the site and its social media accounts, where their money is coming from, or what their motivation is. We investigate their operation - just as Facebook faces tough questions about their role in preserving the integrity of elections around the world.

Presenter: Mike Wendling

(Photo: A montage of Mainstream Network’s website and the site’s logo. Credit: Mainstream Network/BBC)

We investigate the criminals who threaten to expose you on social media, using password hacking.

Imagine you open your email and there’s a message in there from someone that knows some of your personal information – like your laptop password. Not only that, but they’re threatening to reveal your darkest secrets on social media, unless you pay a ransom in anonymous cryptocurrency. That’s been happening to people all over the world - including our reporter Jo Whalley.

Jo finds out how cyber criminals have got hold of people’s personal information and about the huge sums of money people have been paying to the scammers.

Presenter: Mike Wendling

Photo Caption: Photo illustration of hackers

How a viral rumour on WhatsApp led to the lynching of two innocent men in Mexico.

Ricardo Flores and his uncle Alberto were building a well. They set out to buy some supplies, but as it was a warm August day, they decided to take a break along the way. Within hours they were arrested and lynched – beaten and burnt to death by a ferocious mob. Rumours which spread on WhatsApp falsely accused the men of being child kidnappers. And before anyone could stop the residents of Acatlan, a small town in Mexico, a tragedy unfolded – the repercussions of which continue to be felt today.

For the Beyond Fake News season on the BBC World Service, Marcos Martinez went to Acatlan to investigate.

Presenter: Mike Wendling

Photo Caption: A photo of Ricardo Flores, one of the men who was killed.

Hundreds of suicides were linked to the Blue Whale Challenge – but what is the truth behind the claims?

The challenge was described as an online game, where participants were given 50 tasks to perform over 50 days. A report in independent Russian news outlet Novaya Gazeta linked the game to 130 teenage suicides, and a 21-year-old man who was arrested in a case related to the challenge pleaded guilty and is currently in a Russian prison. But others are sceptical that the challenge can definitively be blamed for the tragedies. And in a twist, researchers say the game may not have even existed before the initial media reports.

Presenter: Mike Wendling

(Photo: A blue plastic toy whale. Credit: Getty Images)

The conclusion of our story about two men on opposing sides in the war against misinformation. Fake news writer Christopher Blair finds that the money is drying up because of Facebook algorithm changes, and he’s constantly being hunted by fact-checkers. Meanwhile in Belgium, Maarten Schenk gets a handle on viral misinformation and online lies. It seems like they would be natural enemies. So what happens when they get the chance to speak to each other?

Presenter: Michael Wendling

Photo Caption: Fake News v Facts on a computer keyboard

Anisa Subedar meets two men positioned on opposing sides in the war against fake news. American Christopher Blair makes his living by making up online news stories, and Belgian Maarten Schenk is dedicated to debunking them. The two appear to be natural rivals, but is everything as it first seems?

Presenter: Michael Wendling

(Photo: Fake News headline typed with a typewriter. Credit: Getty Images)

A protest against “manspreading” went viral in Russia – but is it Russian propaganda? Activist Anna Dovgalyuk denies that she staged a stunt where a woman was filmed throwing diluted bleach at the crotches of men whose legs were sprawled out over multiple seats on the St Petersburg Metro. But media reports suggested one of the men was an actor, and a European Union website has described the film as “staged Kremlin propaganda”. So, is it real or just a hoax? And how does it fit into a larger pattern of Russian social media bots and trolls stoking culture wars online?

Reporter: Marco Silva

(Photo: Screenshot from the ‘manspreading’ video that went viral in Russia. Credit: Anna Dovgalyuk)

In Bristol, in the south-west of England, motorbike theft is rife, and criminals use social media to brag about their exploits and even extort money from their victims.

Presenters: Jonathan Griffin, Natalia Zuo

Photo Caption: Volunteer motorbike hunters Martin Bailey and Domonik Wojcik of Stolen Motorcycle Recovery Bristol prepare to track down stolen goods

They decide what you can and can’t see on the world’s biggest social network. Who are Facebook’s content moderators?

Presenter: Anisa Subedar

Photo Credit: Getty Images

The BBC investigative team Africa Eye used open-source techniques to find out who was responsible for a shocking crime.

The government of Cameroon initially dismissed the video as “fake news.” But through open-source investigation – examining details such as buildings, shadows, and uniforms – BBC Africa Eye has been able to find out where the video was filmed, when it was filmed, and who was responsible. Their findings place the blame squarely on Cameroonian forces.

Presenter: Anisa Subedar

(Photo: A still from the video showing the murder of women and children by Cameroonian soldiers)