FOR conspiracy theorists, the bizarre rumours of “pizzagate” didn’t end when a man brought a gun to a Washington restaurant this week in a misguided attempt to rescue non-existent child sex slaves. Instead, the shooting sparked discussion that the conspiracy runs deeper.

On blogs, YouTube channels and internet radio shows devoted to conspiracy theories, the arrest of Edgar Maddison Welch on Sunday was just the latest “false flag,” a term for a cover-up or distraction orchestrated by the government or other powerful figures. The persistent belief in the false-flag theory shows just how stubborn fabricated conspiracies can be, according to experts.

According to police, Welch drove to a restaurant called Comet Ping Pong to investigate the “pizzagate” rumours that Hillary Clinton’s campaign chairman, John Podesta, and other Washington insiders were harbouring child sex slaves there. Police said Welch fired several shots inside the pizzeria on Sunday with a military-style rifle but surrendered peacefully after he found no evidence of a secret paedophilia ring.

There’s no evidence to back up the rumours about the restaurant, a beloved neighbourhood institution in the wealthy enclave of Chevy Chase. In the past year, Comet employees have reported a damaged car, a stolen bag and online harassment; otherwise, it’s never been the subject of a police investigation. But to true believers, the absence of proof is just another sign of a conspiracy and a well-orchestrated cover-up.

James Fetzer, a longtime conspiracy theorist who also believes the Sandy Hook school shooting was a hoax, told The Associated Press that Welch’s visit to the pizzeria was staged to distract the public from the truth of the “pizzagate” allegations.

“There’s no doubt about it in my mind,” said Fetzer, a former philosophy professor and the founder of a group called Scholars for 9/11 Truth. “You see, this is part of the whole idea to smear the alternative media, which are putting out so much more truth than the mainstream.” Welch — a fitfully employed, 28-year-old father of two from North Carolina — is being held without bail. He told The New York Times in a jailhouse interview that he “just wanted to do some good and went about it the wrong way.”

Once a conspiracy theory gains traction, confronting true believers with facts is pointless, said Michael Barkun, a professor emeritus at Syracuse University’s Maxwell School and the author of A Culture of Conspiracy: Apocalyptic Visions in Contemporary America. “When you get to conspiracy theories like this, they’re closed systems of ideas,” Barkun said. “They’re constructed in such a way that there isn’t any evidence you can present to someone who believes them that will lead a believer to change his or her mind.”

“Pizzagate” believers point out references to pizza in Podesta’s hacked emails, which were published by WikiLeaks, and Comet owner James Alefantis’ ties to Democratic donors. They scour Alefantis’ social-media posts and even his restaurant’s menu for “code words” and “symbols” that supposedly reference child sexual abuse. They jump to incredible conclusions based on Podesta’s and Alefantis’ tastes in art.

Fetzer and other conspiracy theorists seized on the fact that Welch had dabbled in movie acting as a giveaway that his visit to the restaurant was staged. Welch wrote a short film and appeared as a victim in a slasher movie alongside a friend, Kathy Sue Holtorf, who told the AP that Welch “never wanted to become an actor.” Blogger Joachim Hagopian, a false-flag proponent, told the AP that conspirators look for “a patsy or stooge” to pose as a lone gunman with an assault rifle. Welch, he said, “fits the pattern” with his acting background.

“He’s got an IMDB (internet Movie Database) profile,” Hagopian said. Conspiracy theorists have made similar claims about parents of the 20 children who were killed at Sandy Hook in Newtown Connecticut, in 2012, calling them “crisis actors” pretending to grieve for non-existent children. Sandy Hook was a false flag meant to promote gun control, the conspiracy theorists said. Just this week, a Florida woman was charged with threatening the parent of a child who died in the shooting because she thought the attack was a hoax, according to federal authorities.

The ultimate false flag in modern times, according to conspiracy theorists, was Sept. 11, 2001. Some believe the World Trade Center towers were destroyed by the government, using bombs or other means, as part of a plot to justify the subsequent wars in Afghanistan and Iraq.

Hagopian said he believes attacks since then — including the mass shootings last year in San Bernardino, California, and this year at a nightclub in Orlando, Florida — also were false flags.

Hillary Clinton has been linked by conspiracy theorists to child sex abuse since the mid-1990s, Barkun said. Andrew Breitbart, the late founder of right-wing site Breitbart News — later led by President-elect Donald Trump’s chief strategist, Stephen Bannon — tweeted in 2011 that Podesta was a “world class underage sex slave op cover-upper.” Radio host and Trump supporter Alex Jones, a well-known conspiracy theorist, said in a YouTube video Sunday that he believes the claims about powerful Democrats abusing children, but he wasn’t convinced Comet Ping Pong had anything to do with it.

“The big bug zapper to distract all the investigators is the D.C. pizza place,” Jones said.

The video was deluged by comments criticising Jones for backing away from the “pizzagate” story.

Conspiracy theories can help believers process genuinely horrific news, such as child sex abuse scandals involving the Catholic Church or Penn State University, said James Broderick, an English professor at New Jersey City University and the co-author of Web of Conspiracy: A Guide to Conspiracy Theory Sites on the Internet. “Having a targeted source of villainy creates, in some people’s minds, a feeling of control,” Broderick said. “Evil isn’t random. It’s a result of these nameable forces that we can target.”