Was he a loner like Ted Kaczynski? Or a young extremist like Timothy McVeigh, disaffected with government?
The suspect arrested in the mailbox bombings in the Midwest was probably both and neither.
As authorities explore the motives behind Luke Helder's alleged incidents, they're finding, first of all, that he doesn't fit the standard profile.
The FBI had been looking for an older white man. Instead, they took into custody Tuesday night a confused and apparently angry college junior in his early 20s.
Police believe Mr. Helder planted the bombs in three states last week, which injured six people and caused many rural Midwesterners to approach their mailboxes with caution.
If Helder did commit the crimes, he made little attempt to conceal them. On Tuesday, the University of Wisconsin's newspaper received a letter with his name on it that included the same text as the messages left with the bombs.
The reasons behind the bombings, however, remain more of a mystery.
"There are some missing pieces here," says Stuart Wright, a sociology professor at Lamar University at Beaumont, Texas, and the author of a coming book on the Oklahoma City bombing.
While there are many examples of young adults and teens committing vengeful acts sometimes on a large scale, such as the shootings at Columbine the latest string of bombings was apparently not motivated by revenge. The alleged bomber didn't appear to know his victims when he planted pipe bombs in their mailboxes. Instead, he left rambling notes with his bombs that talked about government control and the unreality of death.
Furthermore, authorities believe the mailbox bomber acted alone, but Helder is not the prototypical loner, such as the Unabomber.
"This individual, if he actually did commit the crime, was not socially a loner," says Mark Pitcavage, director of fact-finding at the Anti-Defamation League's branch in Columbus, Ohio.
Helder is a student at the University of Wisconsin at Stout, and he sang in a punk rock band. On the band's website, he wrote, "I party, play guitar, and talk online to everyone. That's my life."
But that outward gregariousness may mask a keen sense of isolation, says Ted Kirkpatrick, director of Justice Works at the University of New Hampshire in Durham. "This is the riddle of these young white offenders," he says. "Often, isolation and anger are subjectively constructed qualities of mind."
Among his writings that have been recovered, Helder talks about disaffection, life beyond death, and frustration with government control. His band, called Apathy, released the song "Conformity," which begins: "It's a story how I'm supposed to feel because you told me to."
But the most revealing information about the alleged bomber comes from the letter sent to Helder's college newspaper. The first part of the long, rambling tract repeats in part the note left with several bombs: "If the government controls what you want to do, they control what you can do."
Then it goes on for several pages about the unreality of death, the existence of ghosts, the effect of greed and fear, and government control. "I'm at an advantage in this society, and so is every other spiritually well-rounded person.... The advantage is the knowing that there is NO SUCH THING AS DEATH/VOID/END/NO MORE ... whatever you want to call that notion.... In fearing death," the note continues, "you are forced to work (in turn providing for the government), and conform to society."
It's not clear where the writer picked up these ideas. Helder, an arts major concentrating in industrial design, was attending a philosophy of religion class this semester. And he proved to be a major contributor to class discussions, which included talk about heaven, nirvana, and the afterlife.
"His ideas are not created in a vacuum," says the class professor, Jerry Kapus. "They're coming from somewhere."
What makes Helder stand out is that he allegedly moved from the idea stage to direct and violent action. That takes catalysts, Mr. Wright says. In his 10 hours of interviews with Mr. McVeigh, Wright says he was able to find the influences and events that moved him to take action.
It's not clear what those catalysts could have been in the mailbox bombings. In Helder's hometown of Pine Island, Minn., the biggest employers are farms and the town elevator. The biggest event of the year in the town of 2,000 is a cheese festival.
But even rural areas can be breeding grounds for youth apathy. "The depth of [rural youth's] frustration ... is almost identical and in some ways more far reaching" than in inner cities, says Carl Taylor, a professor at Michigan State University.