You may remember those arrests back in 2009 of three leading white supremacists — Robert Joos, and Dennis and Daniel Mahon — for the 2004 bombing of the racial-diversity office of Scottsdale, Arizona, that seriously injured the office's director and inflicted wounds on two other people. Even though the trail had seemingly gone cold, dogged investigators finally ran these domestic terrorists to ground.

Now it appears that the investigators' relentlessness is about to bring down one of the nation's most prominent white supremacists, according to the SPLC's Bill Morlin:

Tom Metzger — a wily, iconic racist ideologue who has for years espoused “lone-wolf” terrorism — could soon find himself facing criminal charges filed by the federal government he’s excoriated for decades.

Federal investigators, fresh off a related mail-bombing conviction in Arizona, may be pressing for what could develop into a major Justice Department criminal case against “Terrible Tommy” Metzger, as he likes to call himself. Court records filed in three states show the investigators strongly suspect Metzger provided the Arizona bomber with explosive-making instructions, knowing they would be used in the commission of a crime of violence.

At 74, Metzger, who now lives in Warsaw, Ind., has “celebrity status” as the founder of White Aryan Resistance (WAR), court documents say, and is a dean of white supremacists. He’s the last vestige of a generation of revolutionary racist leaders in the United States that included the late Richard G. Butler of Aryan Nations and the late Robert Miles, a one-time Michigan Klan leader and convicted bomber. While those two and many other racist leaders were charged in various criminal cases over the past three decades, Metzger has managed to avoid any serious criminal charges in his 40-plus years of activism.

That may be about to change.

The documents Morlin has dug up make clear that the feds are poised to file indictments against Metzger in short order — because what's become apparent through their investigation is that the Scottsdale bombers were acting at Metzger's behest.

It's a great piece of reporting, so be sure to read it all. I particularly noted this tidbit:

On May 22, 2008, after finding partial DNA profiles on some of the Scottsdale bomb components, ATF agents with a court warrant swabbed the mouths of the Mahon brothers to see if they could obtain a match. Ultimately, they couldn’t make the match, but their visit raised alarms. Two days later, testimony at the later Mahon trial would reveal, Dennis Mahon called his mentor, Metzger.

“I won’t betray you, Tom,” Mahon said over the tapped phone.

“I didn’t think you would,” Metzger replied

Metzger, as Morlin explains, has a long and deep lineage in the white-supremacist movement, and a remarkably broad influence: In many regards, the Minuteman movement of 2005-2010 was Metzger's brainchild. It was Metzger, after all, who in 1978 came up with idea (reportedly inspired by Robert DePugh's radical-right 1960s militia organization that called itself the Minutemen) of a vigilante border watch as part of David Duke's Klan organization, and the first Klan Border Watch soon followed.

Here in the Northwest, Metzger is widely remembered as the neo-Nazi godfather who directed skinheads to assault blacks, leading to the beating death of a Nigerian exchange student named Mulugeta Seraw in Portland in 1988. That wound up putting Metzger out of business for a long while. But like all good zombie haters, he has never completely gone away.

A few years back he finally left southern California, where he had been a resident plague for years, and returned to his hometown of Warsaw, Indiana. He was most recently spotted running for Congress in Indiana in 2010.

Metzger's lifelong project has been to find ways to mainstream white supremacy. He may find that much harder to achieve soon.