Brian Nichols said in letters included in a Georgia Bureau of Investigation case file that he was upset he was being held without bond on rape charges while other inmates awaiting trial were allowed to go free.
He said in one letter that "no black man has ever made a stand such as mine" and insisted the shootings sent a message.
The letters were obtained by The Associated Press.
Nichols was awaiting trial on rape charges in March 2005 when he overpowered a guard and then killed a judge, a court reporter, a deputy and a federal agent.
(Copyright 2011 by The Associated Press. All Rights Reserved.)