Under Georgia law, Superior Court Judge James Bodiford must sentence Brian Nichols to life, and will decide only whether that will include the possibility of parole. A hearing is scheduled for Saturday morning. It is likely Nichols would spend the rest of his life behind bars regardless of the decision.
Nichols expressed no emotion during Friday's hearing.
Prosecutors had urged jurors to sentence Nichols to death after he was convicted last month of murder and dozens of other counts in the 2005 killings.
The 37-year-old was on trial for rape when he grabbed a guard's gun and fatally shot the judge, a court reporter and a sheriff's deputy in the courthouse. He fled and killed a federal agent in an Atlanta neighborhood.
Anything short of death sentence was viewed as a failure for prosecutors. They turned down an offer by Nichols' attorneys last year for him to plead guilty to the murder charges if the state took the death penalty off the table. Both sides have spent millions of dollars since in legal fees to try the case.
Death sentences in Georgia require a unanimous jury decision. The jurors deliberated for more than 30 hours before telling Bodiford around noon Thursday they were deadlocked 9-3, with nine in favor of death and three in favor of life without parole. The judge ordered them to resume deliberating through Friday, and at the end of the day they reported they had "reached a stage where further deliberations will not change an opinion."
The judge then asked them to continue deliberating for two more hours, at the end of which the judge told the courtroom the jurors had failed to deliver a sentence.
In closing arguments of the penalty phase Monday, prosecutors asked the jury for a death sentence while defense lawyers urged jurors to avoid vengeance.
"That's the kind of vengeful, recriminative response that begets more violence," said defense attorney Henderson Hill.
Prosecutor Clint Rucker called Nichols an "extremely dangerous" killer who would try to escape again if sent to prison for life.
"With your help, brick-by-brick, we will rebuild the wall of justice that has been torn down by this defendant," Rucker said.