After serving his time, Miller became an unwelcome figure in the white supremacist movement and was viewed as a traitor, Mark Pitcavage, director of investigative research at the Anti-Defamation League told ABC News.com.
"Ever since [he took a plea deal], most white supremacists don't want anything to do with him," Pitcavage said.
After laying low for a while, Pitcavage said Miller became active again in the past 15 years, taking his hate into the digital age.
Miller operated his own website and posted on the white supremacist Vanguard News Network forums where he used the name "Rounder," according to the Southern Poverty Law Center.
Sources in the Johnson County District Attorney's office and the Johnson County District Court told ABC News that Frazier Glenn Cross will not appear in court today. Cross has not yet been charged, the sources said, and decisions are still being made about what charges he might face. Authorities typically have 48 hours to file charges.
ABC News was unable to reach Cross' family for comment.