Alex Jones and InfoWars: How Sandy Hook families fought back

It was one of the worst school shootings in American history, but some people insist that the Sandy Hook massacre never happened. They post YouTube videos and spread rumours online, and their false theories have been repeated by a media mogul conspiracy theorist who has been linked to Donald Trump. Now, after years of harassment, the families of the victims are fighting back online.

Leonard Pozner clicks on a YouTube video showing his street and the outside of his home. The camera zooms in on his balcony, and his address and a route to his door flash up on the screen.

There's no narration on the video - but there doesn't need to be. The message is clear: "We know where you live."

Because of videos like this one - there are dozens on YouTube, and more appear ever day - Pozner doesn't want to disclose the city where he now lives. He's had death threats and has moved several times in recent years.

Leonard Pozner has been targeted because he's fought back against trolls and conspiracy theorists who make sweeping and false allegations about the murder of his son.

"Noah was just a regular six-year-old child," says Leonard, who's also known as Lenny. "I dropped him off that morning - it really was an ordinary day of getting the kids ready for school.

"Then an hour-and-a-half later it was just the worst nightmare. Worse than any nightmare I could have imagined."

The nightmare began on 14 December 2012 when a young man named Adam Lanza killed his mother and then drove to Sandy Hook Elementary School. In a matter of minutes, he shot dead 20 children and six adults, before taking his own life.

Even in a country where mass shootings are common, Sandy Hook stood out. The pupils were so young, and there were so many of them. Hundreds were traumatised - and many still are - after witnessing the carnage and its aftermath.

And yet despite extensive investigations, external and a report which determined that Lanza acted alone, conspiracy theorists have constructed a fake alternate reality in which the whole thing was an elaborate hoax, staged by the government to try to introduce strict gun control laws.

They seize on small inconsistencies between initial news reports from the chaotic scene and the facts. The more extreme among them have targeted the families of Sandy Hook victims. There have been at least two arrests linked to the hoax theories. On Wednesday, a warrant was issued for a Florida woman who is accused of harassing Lenny Pozner, external.

"We're a luckier family," says Hannah D'Avino, whose sister Rachel was a behavioural therapist at Sandy Hook Elementary School. "I personally will get about like three death threats a year because we don't speak up that much."

On a sunny, late winter's day in New England, Hannah sits in the stately Newtown Public Library, down the road from where her sister was murdered. She recalls her sister's spirit, her profound positive influence on her life, and her work with autistic children.

Her voice is subdued, but quivers with quiet determination.

"My sister was murdered 11 days before Christmas and I consider myself lucky because I don't have a stalker," she tells me. "That's the situation I'm in right now."

Some of the conspiracy theorists are regular visitors to this small hamlet in suburban Connecticut. In addition to the death threats and harassment directed at Lenny, Hannah and others, they've made videos of the school and local area and ask questions of locals and family , and have posted the footage on YouTube.

And their theories have been picked up by one of America's most popular conspiracy theorists, a man who has been linked with President Donald Trump.

The online storm has prompted Lenny to form a volunteer network to track and take down the conspiracy theory videos and websites.

And other Sandy Hook residents are pleading with President Trump, asking him to speak out and help stop the madness.

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Wolfgang Halbig lives in a big yellow house in a sunny, lavishly landscaped gated community in Florida. He's a retired school and safety advisor, and he says that when he first heard news of the Sandy Hook shootings, he was sitting in a chair in his living room, drinking coffee.

"My hairs stood up," he says. "Because they're not protected in the elementary schools."

Halbig donated money to the Sandy Hook families. But he soon became both obsessed with the tragedy - and, somehow, convinced that it never happened.

"I think 14 Dec 2012 is an event that was in planning for a long, long time," he tells me. "I think it probably took them two, two-and-a-half years to write the scripts for all the participants that were invited to participate in that exercise - or drill as I will call it."

Halbig has since devoted years of his life to "exposing" what he thinks is a government plot. He started a website. He's revealed personal information about the victims of his attacks, including names, addresses, legal documents and financial information. And he's personally travelled to Sandy Hook a number of times.

"I call it an illusion. The biggest government illusion that's ever been pulled off by [the US Department of] Homeland Security."

In his office, ghoulish blown-up pictures of the crime scene mingle with pictures of his family and his days as an American football player. His so-called evidence consists of a string of tiny details, small anomalies which are for the most part easily explained by the inchoate nature of a horrific breaking news event.

"I'll be honest with you," he says, "if I'm wrong, I need to be institutionalised."

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Conspiracy theories are a perennial feature of American life. But now they can be picked up by extremists and spread virally through social media. And that process has been fuelled by America's deeply partisan political environment.

Hundreds of videos online are pushing false Sandy Hook narratives. Collectively, they have millions of views. Falsehoods are repeated by Twitter s and on Facebook.

Still, the theories might have stayed quarantined in some of the darker corners of the internet, were they not picked up and amplified by one of America's most popular conspiracy theorists.

Alex Jones is a talk show host and the founder of the multimedia portal Infowars. Regular listeners and readers are used to his rants on everything from 9/11 to attacks across Europe. And on several broadcasts he embraced the Sandy Hook conspiracy theorists. Less than two years after the attacks, he welcomed Halbig on his programme and talked about an Infowars story headlined "FBI says no one killed at Sandy Hook, external".

"Internet sleuths immediately took to the web to stitch together clues indicating the shooting could be a carefully-scripted false flag event, similar to the 9/11 terror attacks, the central tenet being that the event would be used to galvanize future for gun control legislation," the story stated.

He returned to the theme several months later on his radio show, external: "I've had the investigators on, the state police have gone public, you name it - the whole thing is a giant hoax. And the problem is, how do you deal with a total hoax? How do you even convince the public something's a total hoax">