The Suffolk County District Attorney’s office is still combing through the racist and anti-Semitic writings of a Winthrop man for clues as to why he carried out a murderous rampage that began in a stolen truck and ended in a gun battle with police, in which he was shot and killed. Before it was all over, Nathan Allen gunned down two Black residents in what authorities believe was a hate crime.

Allen appears to fit in with a difficult profile: unaffiliated with particular groups, and motivated by hate.

Individual actors pose a challenge to authorities trying to prevent radicalization and attacks, said Bruce Hoffman, the senior fellow for counterterrorism and homeland security at the Council on Foreign Relations.

“In years past, we had individuals that we could almost chart their trajectory from political awakening, political activism to political radicalism to eventually crossing the line and picking up a gun or throwing a bomb. And it was in service to some organization they that they belonged to, or they were following the orders or instructions of some leader,” Hoffman said. “But with this horrible incident in Massachusetts, it conforms to an emerging pattern that we've seen in recent years, where it's a lone individual with no organizational affiliation.”

Others argue prevention and intervention on such an individual scale are difficult or impossible to pull off. Clinical psychologist Alice LoCicero, the author of “Why ‘Good Kids’ Turn into Deadly Terrorists” about the Boston Marathon bombers, says the gunman’s rampage cannot be disassociated from the surge in right-wing violence nationally.

“It doesn't take an extraordinary evil person to become a racist or even a murderer," LoCicero said. "We can't predict on an individual basis who's going to become violent in the future.”

“The situation and the community are very powerful in this regard. Leaders are powerful,” she went on. “Many of our leaders who are looked up to are acting as if the white supremacy violence either didn't happen or wasn't much of a big deal, including the January 6th incursion in the Capitol. ... Where we have that kind of denial and failure of leadership, the community is at risk.”

But even understanding larger national trends begs more questions about particular actors. Many people are political extremists but not violent in pushing for their agendas, Hoffman said. The question becomes, according to Hoffman, what triggers an individual to take violent action?

Racist and otherwise bigoted online forums and videos have become something of a crucible for white supremacists. Shooters’ online media consumption — and posts — are now one of the first steps into understanding their mentalities and how they acquired their beliefs.

Examples of similar killers have emerged in recent years, such as Dylann Roof, who killed nine people at a Black Charleston, N.C., church in 2015.

“With [Roof], all the accounts of his life leading up to that incident would have set off alarm bells to anyone who had been tracking or following him,” Hoffman said. “I mean, he was on social media. He expressed openly and repeatedly racist views. He was clearly in a glide path towards violence. Nathan Allen in Massachusetts, who committed these terrible crimes last Saturday, from all indications lived a completely normal life.”

Keeping communities safe, LoCicero argues, can only be done with a broader approach. “There are actually no lone wolves, I think, at least not in their own mind. I think what happens is that people who act as this young man acted, most of them think of themselves as part of some larger community of white supremacists,” she said. “If we fail to have a general condemnation of that kind of thinking, we put our whole community at risk.”