WASHINGTON • Edgar Welch, a 28-year-old father of two from Salisbury, North Carolina, recently read online that Comet Ping Pong, a pizza restaurant in Washington, DC, was harbouring young children as sex slaves as part of a child abuse ring led by Mrs Hillary Clinton.
The articles making those allegations were widespread on the Internet, including Facebook and Twitter.
On Sunday, Welch drove for about six hours from his home to Comet Ping Pong to see the situation for himself, according to court documents.
Not long after he arrived, the police said, he fired an AR-15 assault rifle. He was arrested and the police found a rifle and a handgun in the restaurant. No one was hurt.
In court on Monday, a heavily tattooed Welch was ordered to be held in custody. He was charged with four counts, including felony assault with a deadly weapon and carrying a gun without a licence outside a home or business.
According to the police, he told them that he was armed in order to help rescue children, but surrendered peacefully after finding no evidence that "children were being harboured in the restaurant".
Unbeknown to Welch, what he had read online were fake news articles.
The false articles against the pizzeria began appearing on social networks and websites in late October, not long before the US presidential election, with the restaurant identified as the headquarters for a child trafficking ring.
The shooting underscores the stubborn lasting power of fake news and how hard it is to stamp out.
The articles were soon exposed as false by publications including The New York Times, The Washington Post and a fact-checking website Snopes. But that did not quash the conspiracy theories - instead, it led to the opposite.
Twitter, Facebook and Instagram were flooded with more attacks against the pizzeria as believers in the child trafficking conspiracy became more zealous.
One post on Twitter by "Representative Steven Smith of the 15th District of Georgia" warned that what was fake was the information peddled by the mainstream media. It was retweeted dozens of times.
In fact, that post was not from a real lawmaker and the alleged electoral district is not real either.
Mr Jeffrey Marty, a Florida lawyer, claims that he posed as 'Rep Steven Smith', adding that he was frustrated with the way the mainstream media covered the election and that he believed most of his 24,000 followers know his account is a parody.
But Mr Marty, who has tweeted links to other fake news stories, declined to say whether he actually believed the Comet Ping Pong allegations. "I just think you need to investigate," he said.
A surge of new fake articles amplified the original pieces, now linking the child abuse ring - known as Pizzagate - to a global paedophilia ring .
Not long after the police arrested Welch, some individuals on Twitter also claimed Welch was an actor used by the mainstream media to divert attention from the alleged crimes at Comet Ping Pong.
Mr James Alefantis, owner of Comet Ping Pong, has repeatedly refuted the fake news articles.
He wonders if a previous communication with Mrs Clinton's campaign chairman may have made him a target.