A secret FBI report, obtained by ABC News, identifies 22 domestic terror organizations as the current subjects of 338 active FBI field investigations.
The Aryan Nations, and other white supremacist groups, are cited in the report for hate crimes, fire bombings, threats via mail, as well as robberies and murders. The National Alliance, one of the largest neo-Nazi organizations in the world, is subject to 51 FBI investigations alone, according to the report.
In fact there are "ticking time bombs," said Brian Levin, director of the Center for the Study of Hate & Extremism at California State University, San Bernardino, "who have the capacity, skill and hatred to carry out acts worse than what Timothy McVeigh carried out 10 years ago."
Levin, and other terrorism experts, say that the Internet has become the principal recruitment tool, attracting the loners and the disturbed who boast of finding viable U.S. targets.
"We are likely to see more terrorist attacks by lone wolves, or small cells," Levin said, "They're in their bedroom accessing bomb-making information on the Net, and accessing hateful rhetoric which empowers them."
James P. Wickstrom, who calls himself the world chaplain of the Aryan Nation, uses "Death to the Jew" as a mantra of sorts. He also regularly calls for the deaths of government leaders, including the president.
"There is none of them in this Cabinet that damnably deserves to breathe the air in this country today," Wickstrom said in a speech given at the Aryan Nations World Congress in Pennsylvania in July 2002.
Federal officials say his calls to action are not unlike those of the leader of al Qaeda, Osama bin Laden. Wickstrom has declared himself an enemy of the United States government.
"I tell you we do not need this Congress and legislative body," he said in the same speech. "We don't need these vile bastards telling us what to do on our property and with our water and with our children. We don't need to tell them we have to wear a seat belt. We don't need have to be told anything."
Wickstrom's popular Web site, part of the "United Aryan Terror" Web ring, and others, portray executed Oklahoma City bomber Timothy McVeigh as a martyr and patriot.
"The Internet is where law enforcement should be looking," said Levin. "Because that is where the next Timothy McVeigh probably is right now."
Several of the groups under FBI investigation sponsor neo-Nazi concerts and produce their own records as a way to raise money.
And there is growing concern about the recruitment of disaffected teenagers by domestic terror groups.
Just recently, officials in Riverside, Calif., discovered a huge collection of automatic weapons, narcotics and Nazi paraphernalia -- the efforts, they suspect, of a volunteer high school football coach and the teenagers he had recruited for a neo-Nazi group. Among the weapons cache, Riverside County Sheriff's Department deputies and the FBI found over 75 firearms, 15,000 rounds of ammunition and several bulletproof vests. The coach and 18 others are awaiting trial.
"We were like, wow, here we are with narcotics, we have over a hundred weapons and we have this group that is promoting hate," said Sgt. Earl Quinata, spokesman for the sheriff's department. "It was a very dangerous situation."
Vic Walter, Avni Patel and Jessica Wang contributed to this report.