“Investigators need to take a serious look at far left groups like #Antifa when investigating the bombs sent to Soros, Obama, and the Clintons,” he wrote in a now-deleted tweet. “These smell like the false flag tactics of unhinged leftists who know they’re losing.”

‘Acts of terror’: Bombs sent to Hillary Clinton, Barack Obama and CNN

Cardillo wasn’t alone. Bill Mitchell, a pro-Trump Twitter mainstay and radio host, was also convinced that the real target of the potential explosive devices was the political power of Republicans.

“These ‘explosive packages’ being sent to the #Media and high profile Democrats has Soros astro-turfing written all over it so the media can paint the #Republican Party as ‘the dangerous mob.’ Pure BS.” Mitchell wrote. His tweet, which is still live on Twitter, has more than 6,000 retweets.

Online speculation is an inevitable result of a breaking news story on the internet. On the pro-Trump internet, that speculation has increasingly helped to push the once fringe idea of politically motivated “false flag” attacks into the mainstream.

Within minutes of the news of the suspicious packages, the “false flag” narrative began circulating in pro-Trump spaces like the r/The_Donald subreddit. Rising posts linked to articles about Bill Ayers, one of the founders of the radical Weather Underground organisation, which claimed responsibility for a series of bomb attacks in the 1970s. Another rising post said, “FALSE FLAG. When you hear the MSM screaming about attempted violence by Trump supporters two weeks before Midterms just remember what leftists are capable of.”

Trump condemns ‘abhorrent’ attempted bomb attacks

Beyond the internet, radio host Rush Limbaugh suggested the bombs were intended to shore up Democrats in the midterm elections and saying of the timing “there’s a reason for this”. He added that “Republicans just don; t do this kind of thing.”

Discovery of the devices came just after a big success for the pro-Trump internet. Ever since Trump’s inauguration, Trump’s online base has amplified and fed a meme claiming that “violent leftist mobs” present a major, immediate, threat to the safety of the president and all of his supporters. During the confirmation process for Justice Brett Kavanaugh, that meme became the mainstream conservative reaction to protesters who opposed Kavanaugh’s elevation to the Supreme Court.

Stoking fears of the “angry mob” of Trump opponents has become a key part of the GOP’s strategy to energise their voters for the midterms.

Many Republican leaders set aside the “liberal mob” talk to condemn the attacks, including House Majority Whip Steve Scalise, and Vice-President Mike Pence.

But even as some pro-Trump media personalities started to walk back their “false flag” claims, they referred to the “liberal mob” meme to justify that speculation in the first place.

Michael Flynn Jnr, who deleted his tweet calling the situation a “total false flag operation,” followed up with a series of tweets claiming he was just asking questions, and that the timing of the incident was “suspicious.” Flynn, the son of Michael Flynn (who was briefly Trump’s national security adviser), has previously spread the Pizzagate conspiracy theory that Hillary Clinton and other top Democrats were involved in a paedophilia ring based in a Washington pizza restaurant.

“You see? The left already blaming the @GOP for this … If I’m wrong about this being a political stunt, I’ll own up to it. But timing is everything folks. And the timing given how close we are to midterms is HIGHLY SUSPICIOUS!,” he tweeted.

Frank Gaffney, an anti-Muslim conspiracy theorist who has previously hosted Secretary of State Mike Pompeo on his radio show, also invoked the leftist mob in his own assessment of the news: “None of the leftists ostensibly targeted for pipe-bombs were actually at serious risk, since security details would be screening their mail. So let’s determine not only who is responsible for these bombs, but whether they were trying to deflect attention from the Left’s mobs.”

False flag theories have always been popular among conspiracy theorists, who use them to attempt to discredit any event that proves inconvenient to their worldview.

But it’s only the past few years – as social media networks balloons in influence and President Trump inserts conspiratorial thinking into the national discourse, including some ideas that originate on social media – that false flags have become almost a feature of the wider landscape.

The first viral false flag theory may have been the 9/11 “truther” movement, whose devotees spammed out blog posts and suspect documentaries claiming the US government secretly masterminded the September 11, 2001, attacks as a pretext to start the Iraq War. (In some versions, CIA operatives imploded the World Trade Centre with demolition charges; in others, the government used cruised missiles disguised as planes.)

But since Trump’s election in 2016, false flag fantasies have become almost as regular as the tragedies they are used to discredit:

●A baseless theory spread virally soon after the Parkland school shooting in February, claiming the US government had staged the massacre as an excuse to seize people’s guns. The children who survived the shooting were “crisis actors,” according to believers, as were the grieving parents. Nearly identical rumours have circulated online after many other school shootings.

●Two conspiracy theorists drove to a church in Sutherland Springs, believing the Department of Homeland Security had staged a recent mass shooting there, and demanded the church pastor prove to them that his dead 14-year-old daughter had ever existed.

●Widespread claims that a man who shot a gun inside a Washington pizza restaurant in late 2016 (he believed it was a secret child sex dungeon at the heart of the Pizzagate conspiracy) was actually a false flag actor trying to discredit other conspiracy theorists.

●The mega-viral QAnon conspiracy theory, a core component of which is the belief that special counsel Robert Mueller is only pretending to investigate Trump’s inner circle for possible crimes – and is actually allied with Trump in a global war against liberals.