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.