The far-right “Boogaloo” civil-war movement—whose devotees comprised a significant portion of the so-called “Patriots” who besieged the Capitol last Jan. 6—may have largely faded from public view over the past year, but its followers continue to plot violence from the fringes. Just this past month, two “Boogaloo” devotees in Washington state were charged with making bombs targeted at law enforcement officers.

Its lingering presence, moreover, is stark evidence of the pernicious effect of social media platforms’ laissez-faire approach to such extremism, particularly on Facebook, where much of the “Boogaloo” movement gained traction in its formative years. Facebook (and its now-parent company Meta) has since made a public relations-driven effort to purge the movement from its platform, but the damage was already done—as the family of one of its victims is now contending in a lawsuit intended to hold the company accountable.

The lawsuit, filed by the sister of David Patrick Underwood—the federal security officer who was gunned down by two “Boogaloo” adherents in Oakland in June 2020—argues that Facebook’s algorithms drew the killer and his coconspirator together, enabling their vicious crimes.

“The shooting was not a random act of violence,” the lawsuit contends. “It was the culmination of an extremist plot hatched and planned on Facebook by two men who Meta connected through Facebook’s groups infrastructure and its use of algorithms designed and intended to increase user engagement and, correspondingly, Meta’s profits.”

Angela Underwood Jacobs contends that Facebook officials were aware that their platform was a recruitment tool for Boogaloo believers, but it failed to stop recommending their pages until after Underwood’s death.

“Facebook Inc. knew or could have reasonably foreseen that one or more individuals would be likely to become radicalized upon joining boogaloo-related groups on Facebook,” the suit states.

Underwood was shot with a sniper rifle the night of May 29, 2020, by “Boogaloo Boi” Steven Carillo, 32, a former Air Force staff sergeant. He was accompanied by a man he met in a Boogaloo Facebook group named Robert Justus, 30.

The morning before the Oakland attack, Carrillo and Justus had an exchange: “It’s on our coast now, this needs to be nationwide. It’s a great opportunity to target the specialty group soup bois [a Boogaloo reference to federal law enforcement agents],” Carrillo wrote.

“Let’s boogie,” answered Justus.

“Go to the riots and support our own cause. Show them the real targets,” Carrillo wrote in another post. “Use their anger to fuel our fire. Think outside the box. We have mobs of angry people to use to our advantage.”

Underwood Jacobs’ suit contends that if Facebook altered its algorithm so that it was not recommending and promoting Boogaloo groups, Carrillo might not have connected with his accomplice. “Meta’s negligent conduct was a substantial factor in Carrillo and Justus meeting on Facebook, planning on Facebook to carry out acts of violence against federal law enforcement officers,” the lawsuit says.

“Facebook bears responsibility for the murder of my brother,” Underwood Jacobs said.

“These claims are without legal basis,” Facebook spokesman Andy Stone retorted.

Legal experts say the lawsuit faces an uphill climb, including the legal shield protecting internet platforms from culpability for the behavior of their users. “There have been a number of lawsuits trying to establish that Facebook is liable for how violent groups and terrorists used their services,” said Eric Goldman, a professor at Santa Clara University Law School. “And courts have consistently rejected those claims because services like Facebook aren’t responsible for harms caused by people using the service.”

But researchers who monitor extremism, as The Guardian’s Lois Beckett observes, say that  the single platform that could have made the most difference in reeling back the spread of the Boogaloo movement was Facebook—mainly because Facebook was the primary platform where it organized from 2018 to early 2020, often in plain sight.

Carrillo, it later emerged, had connected with a number of other “Boogaloo” militants through Facebook, and they had created their own secretive militia—dubbed “Grizzly Scouts”—geared toward assassinating law enforcement officers. They discussed disguising themselves as antifascists so that leftists could be blamed for the violence.

And indeed they were, despite the reality that Underwood was assassinated by a far-right extremist. Both Sen. Ted Cruz and then-Vice President Mike Pence publicly attacked antifascists by blaming them for the Oakland shootings.

The two Washington state “Boogaloo Bois” recently arrested by the FBI—Daniel Anderson, 26, of Kennewick and Connor Goodman of Auburn, part of a larger militia group who called themselves the “Verified Bois”—were arrested after a grand jury indicted them for constructing explosive devices, with which they discussed targeting police officers.

The men obtained high-powered fireworks and the ammonium-nitrate target Tannerite to build their bombs with. Anderson called the explosives “distraction devices” that could “throw birdshot at least 20 yards,” but added that they “aren’t training tools. I wouldn’t be anywhere near this thing. It’s going to throw shrapnel like a MF.”

Anderson and Goodman, along with other Verified Bois members, “practiced small unit tactics, raids, firearms handling and manipulation, and survival skills,” their indictment said. During these trainings, the two allegedly discussed attacking police personnel they perceived to be aggressive.

Goodman talked with other Verified Bois at a May 2021 meeting about his plan to load up a vehicle with Tannerite, which he said would turn the car into an “improvised explosive device.”