Law enforcement agents are now trying to figure out how and why this 21-year-old man transformed his alienation into calculated rage — an attack in which Roof is accused of killing nine African Americans at a church Wednesday. Not only did he drive two hours from his home, but he also spent an hour praying with his victims, authorities say.
So far, the portrait they are drawing of Roof is that of a "lone wolf," someone disconnected from traditional hate or terrorist groups, who looked online for his inspiration and struck without detection.
Analysts say the rise of lone wolves is one of the biggest trends in terrorism. Not only are lone wolves harder to predict, but, without a group to hold them accountable, they are also capable of potentially more unrestrained violence.
A law enforcement official on Friday called Roof "a person drifting through life who had access to a computer, a classic lone wolf."
He said that investigators will review Roof's Internet history and other evidence for more clues to whether he was visiting white supremacy websites. "He linked himself to this cause, obviously," said the official, speaking anonymously because the case is developing.
The official said Roof may have chosen the Emanuel AME Church in Charleston, S.C., as the site of his violence because it is a prominent symbol among African Americans.
But the source emphasized that investigators so far have not found a "figure or group" that may have collaborated with Roof or directed him to the church in Charleston.
A local leader of a group that has been labeled a neo-Confederate hate organization by the
"I'm pretty well tied in with all the Southern groups in the area," said Lourie Salley, a board member and former South Carolina chairman of the League of the South, who practices law in Roof's hometown of Lexington. "As far as I know, he's never had any contact with any of us."
Salley, who strongly denies that his group is white supremacist, called the church attack a "heinous crime" that would leave Roof in "a special place in hell."
A February study by the Southern Poverty Law Center examined more than 60 domestic terrorism incidents between 2009 and 2015 and found almost three-quarters were carried out or planned by a single person. Ninety percent were the work of no more than two.
Experts say lone-wolf attackers are often people with stress and instability in their lives, previous criminal behavior, few close personal relationships and a tendency to let anger fester over perceived wounds, including things that did not happen to them personally.
Though Roof's life has not yet been fully sketched out, at least some of that description appears apt.
Roof moved between schools in Richland County and Lexington County, according to school records, none of which showed him advancing beyond the ninth grade. He had recently been arrested on suspicion of petty crimes that followed drug possession, and he told police that he had been unable to get a job.
"The lone wolf, oftentimes, is really living in a world of his own pain and doing, and feels that he's not understood, and wants power and control," said Brian Levin, director of the Center for the Study of Hate and Extremism at Cal State San Bernardino. "And I think that's what we saw here."
An old friend, Joseph Meek Jr., told the Associated Press that Roof had drifted away from him five years ago, only to reemerge in recent weeks with strong views about recent racial incidents and a general belief that black people were "taking over the world."
It's unclear where Roof may have developed his racist views. His family members have said little.
"Everyone keeps asking, 'Well, how'd he turn out like this? Why'd he do it?'" said Carson Cowles, his uncle, in an interview. "All I can tell you is there wasn't anyone in my family that did this, made him this way."
Experts say isolation from hate groups can actually increase the anger and sense of righteousness among lone wolves.
"If you're active in a movement, a lot of your energy … can be soaked up by other things. Meetings, rallies, demonstrations," said Mark Pitcavage, director
of the Anti-Defamation League's Center on Extremism, who recently wrote an academic paper analyzing about 35 lone killers in the U.S. over the last 20 years. "If you're just sort of stewing in your own juices, things can kind of build up."
Far-right domestic groups have also long glorified "leaderless resistance," a concept defined in an essay by white supremacist Louis Beam that gained traction in the movement in the early 1990s.
"We find lone wolves across the entire political or religious spectrum," said Jeffrey D. Simon, visiting lecturer in the Department of Political Science at UCLA and author of "Lone Wolf Terrorism: Understanding the Growing Threat."
Simon's partial list of recent notables bears out their diversity: