He faces charges -- including armed carjacking and armed robbery -- in the beating of James Privott, 76, last August while the victim was fishing in a south Baltimore park. Court documents show he confessed to the beating and said it wouldn't have happened if the victim had been white.
Lockner will be tried alongside 18-year-old Zachary Watson, who faces the same charges. Watson told police he didn't participate in the beating. A second teenager had his case moved to juvenile court.
Lockner is an avowed white supremacist who's been incarcerated for most of the past decade.
Privott was able to get away from his attackers. He lost two teeth and suffered injuries to his face.