Pardon me if this has already been linked (I imagine it has been):

Rightwing extremism? What rightwing extremism?

Armored gunman, 4 people dead in Arizona shooting

J. T. Ready, a neo-Nazi and member of the Minuteman Civil Defense Corps, was among the dead. It is still unclear what role he played in the shootings, although sources told azcentral.com that he was the shooter.

[…]

Law enforcement agents had been nervous about Ready, according to a 2010 story by the Associated Press, not just because he led a militia group that watched for immigrants crossing illegally into the United States, but because he was heavily armed and a self-proclaimed neo-Nazi.

usnews.msnbc.msn.com