(CNN) -- The weekend killings at a Sikh temple in Wisconsin have brought a furious fringe genre of American music out of the background and to the front of the mix.
So called hate-rock bands like the one once led by temple gunman Wade Page are increasingly important to the U.S. white supremacist movement, drawing in new recruits and bringing in cash, according to groups that keep tabs on those groups.
Page was shot to death by police on Sunday after killing six people at the Sikh temple in Oak Creek, Wisconsin, a Milwaukee suburb, investigators say. He led a North Carolina-based band called End Apathy for the past several years and played with several groups "in the leading tier" of the genre over the past decade, said Devin Burghart, author of "Soundtracks to the White Revolution," a book on the subculture.
Bands like Page's are instrumental to bringing disaffected teens into the movement, he said.
"They're isolated individuals, often with behavioral problems, perhaps problems at home who are looking for a new familial bond as well as a sense of identity and belonging," said Burghart, the head of research for the Institute for Research and Education on Human Rights in Spokane, Washington.
"So white-power music comes in," he said. "It bridges the gap between healthy youth rebellion and hardcore white supremacy, providing that kind of Aryan identity."
Once drawn in, hate groups "get these younger kids to do their bidding," said David Gletty, who once infiltrated the movement for the FBI.
"They brainwash them into believing that hate is the way to go and following them is the only way to go, and that there are other races of people that are against the white people," Gletty told CNN.
Meanwhile, the music has become a multimillion-dollar business for a handful of labels, Burghart said. Some of those may press as many as 25,000 copies of a well-known band, a respectable figure for an independent imprint, but most produce far smaller numbers of CDs or records.
"It really provides the bulk of the financing, such as it is, that neo-Nazi and related kinds of groups are able to earn in this country," added Mark Potok, who tracks white supremacist groups for the Alabama-based Southern Poverty Law Center.
The movement has followers in both Europe and North America. But in the United States, the First Amendment offers the bands and their labels a protection that they don't have across the Atlantic. Many European countries have restricted neo-Nazi activities, symbols and statements since the horrors of World War II, so the recordings are traded largely on a black market there, Burghart said.
White supremacist groups hold occasional music festivals that typically draw about 200 fans, usually held on rural private land because of the difficulty of booking public venues, Burghart said. They're raucous, often violent affairs in which some of the fissures among different groups flare into "fisticuffs and scuffles," he said.
And Gletty told CNN's "The Situation Room" that the crowds "have the mindset of a pit bull."
"In one moment they're like a mother pit bull licking their little puppies, and then, 10 seconds later, they're just off the wall doing something crazy," he said. "Their mind snaps, but they love this ... the ones that commit this violence, they thrive on this, and most of them really feel that it's the government pushing them towards this."
But while the stereotype of the skinhead is a brawling, blue-collar kid, "today it's far more of a middle class or even upper class phenomenon," Burghart said.
He cites the example of Benjamin Nathaniel Smith, a young neo-Nazi who targeted blacks, Jews and Asians in a weekend of drive-by shootings in Illinois and Indiana in 1999. Police say Smith killed two people and wounded another 10 before fatally crashing a stolen minivan during a police chase.
"Ben Smith was recruited through the white power music scene," Burghart said. "He was from an upper, upper middle class family from the wealthy Chicago suburbs. He went to the most prestigious high school in Illinois. He came from a stable family and yet was attracted to the movement ... He's more of the model of the folks today than in the past."
That has changed the movement around them as well, as members set up businesses ranging from tattoo parlors to cable-installation contractors to support their activities.
"It increases the desire for a kind of professionalization in the scene," he said. "So instead of doing this simply as a passion, as true believers, they saw a business model that they could bring to the scene."
CNN Correspondent Drew Griffin contributed to this report.