In and out of prison on drug and violence convictions, Bryan was obviously prone to making mistakes. The worst, ultimately, turned out to be one he made in prison: he joined the Aryan Circle, a neo-Nazi prison gang.
Released from prison, he tried to get free of the gang life - but the gang life was less willing to release him than the State's hospitality.
His next mistake was fighting back a little too effectively when Aryan Brotherhood thugs jumped him. Nobody died, but one of the AB thugs nursed a grudge. When the Brotherhood ran into Bryan one April predawn, they tortured him to death, murdered him, and then chopped up the corpse.
As to the Aryan Circle - the big scary prison gang Bryan had joined for protection? Their leaders considered the matter. Since Bryan was trying to turn his life around, and his killers were scary murderers, the AC leadership bravely declared that they didn't REALLY care about him anyhow.