When the FBI discusses the threat of domestic extremism, they often refer to "lone actors," known alternatively as "lone wolves."
"Because they act alone and move quickly from radicalization to action—often using easily obtainable weapons against soft targets—these attackers don’t leave a lot of “dots” for investigators to connect, and not a lot of time in which to connect them," Wray said earlier, in a September 2021 address.
Specifically with regard to racially motivated violence, a top FBI counterterror official said in a 2019 Congressional hearing that the current threat was "decentralized and characterized by lone actors radicalized online" -- a change from organized groups in the 1980s and early 2000s.
While the DOJ and FBI did not use the term in their statements about the alleged Buffalo gunman, some experts say that classifying white supremacist shooters as lone actors or lone wolves belies the growing threat of racist extremism in the United States and the leaderless transnational movement that underpins it.
Policy research organization Center for Strategic and International Studies (CSIS) found that alleged right-wing attacks and plots have accounted for the majority of all U.S. terrorist incidents since 1994. CSIS found that right-wing extremists were responsible for more than 500 of the 893 terrorist attacks and plots between 1994 and 2020.
Kathleen Belew, a historian who studies the white power movement, testified before Congress in another 2019 hearing about the tactics that have allowed such extremism to remain primarily in the shadows.
"This movement connected neo-Nazis, Klansmen, Skinheads, radical tax protesters, militia members, and others," testified Belew. "It brought together people in every region of the country. It joined people in suburbs and cities and on mountain tops. It joined men, women, and children; felons and religious leaders; high school dropouts and aerospace engineers, civilians and veterans and active-duty troops."
She said two effective strategies that the movement still employs started in the 80s: the use of computer-based social network activism and the implementation of leaderless resistance.
Online forums and social media have continued to serve as vital tools for spreading racist ideologies, misinformation, conspiracies and hate. It's led to the rapid radicalization of people like the alleged Buffalo shooter, Payton Gendron, according to an ABC News analysis of what authorities have identified as Gendron's writing.
Gendron has been indicted by a grand jury for first-degree murder, but all charges remain under seal. He will be arraigned on July 9. Gendron was initially charged with one count of murder, to which he pleaded not guilty and was ordered to be held without bail.
The FBI and DOJ have not responded to ABC News' request for comment.
"The online environment serves terrorists in several very valuable ways," said Daniel Byman, a professor at Georgetown University and a senior fellow at Brookings Institute. "It gives them very easy reach. Ideas kind of ricochet around the world very rapidly and people can form communities around the world."
Alleged Buffalo gunman's online interactions
Gendron said he was radicalized in recent years after engaging with white supremacists online, according to a document authorities say details his plans and motives that has been reviewed by ABC News.
These documents show Gendron self-radicalizing when the pandemic began, spending inordinate amounts of time reading hate posts on social media, a senior law enforcement source briefed on the case told ABC News.
In the months and weeks leading up to his alleged attack on the Buffalo supermarket mass shooting, he became increasingly violent in tone on online platforms, according to the source.
In the document allegedly detailing his plans for attack, he expressed racist and antisemitic sentiments and declared white supremacist conspiracies as his motive behind the attack.
"Violent extremists are increasingly using social media for the distribution of propaganda, recruitment, target selection, and incitement to violence," FBI officials Michael C. McGarrity and Calvin A. Shivers said in a 2019 statement to the House Oversight Committee during a hearing on white supremacy.
"Through the Internet, violent extremists around the world have access to our local communities to target and recruit like-minded individuals and spread their messages of hate on a global scale."
There are many individuals like Gendron, as well as small networks of activists, working toward the common goal of white supremacy without being tied to one specific movement, organization or effort -- the tactic of leaderless resistance, Byman said.
According to the Southern Poverty Law Center, Louis Beam, a well-known white nationalist, wrote a widely circulated essay popularizing the concept.
"Leaderless resistance has had a much more catastrophic impact in clouding public understanding of white power as a social movement," Belew said.
This is why such attacks have become difficult to prevent, according to Seth Jones, the senior vice president of CSIS.
Individual efforts can be harder to track: "Unlike the 9/11 terrorist attack which was an actual plot by an organized group, the vast majority of attacks and plots that we see in the United States are happening by individuals, or a very small network of individuals that make a decision to use violence," Jones told ABC News.
He said leaderless resistance tactics are designed to be difficult to track, allowing violent plots and motives to slip under the radar.
"The problem is the plots are not orchestrated, planned, and then executed by the leaders of any of these organizations," he said. "They're essentially either foot soldiers or individuals that have been reading their propaganda online or interacting with people in person."
Thinking of individual actors as "lone wolves" ignores the captive audience of white supremacists who remain in the wake of such a tragedy, experts say.
"It's a much bigger issue than we're seeing just with this particular attack," Jones said.