The man who bludgeoned former House Speaker Nancy Pelosi’s husband with a hammer last year consumed a steady diet of right-wing conspiracy theories before an attack that took place with the midterm elections less than two weeks away.

As the 2024 presidential campaign heats up, experts on extremism fear the threat of politically motivated violence will intensify. From “Pizzagate” to QAnon and to “Stop the Steal,” conspiracy theories that demonized Donald Trump’s enemies are morphing and spreading as the front-runner for the 2024 Republican nomination aims for a return to the White House.

“No longer are these conspiracy theories and very divisive and vicious ideologies separated at the fringes,” said Jacob Ware, a research fellow at the Council on Foreign Relations who focuses on domestic terrorism. “They’re now infiltrating American society on a massive scale.”

A federal jury on Thursday convicted David DePape of attacking Paul Pelosi at his San Francisco home on Oct. 28, 2022. Before the verdict, DePape testified that he had intended to hold Nancy Pelosi hostage and “break her kneecaps” if the Democratic lawmaker lied to him while he questioned her about what he viewed as government corruption. She was in Washington at the time of the assault.

In online rants before the attack, DePape echoed tenets of QAnon, a pro-Trump conspiracy theory that has been linked to killings and other crimes. A core belief for QAnon adherents is that Trump has tried to expose a Satan-worshipping, child sex trafficking cabal of prominent Democrats and Hollywood elites.

Trump has amplified social media accounts that promote QAnon, which grew from the far-right fringes of the internet to become a fixture of mainstream Republican politics.

Many rioters who stormed the Capitol on Jan. 6, 2021, espoused QAnon’s apocalyptic beliefs online before traveling to the nation’s capital for Trump’s “Stop the Steal” rally that day. A message board formerly known as TheDonald.win was buzzing with plans for violence days before the siege.