The jury reported Thursday that it was unable to reach a unanimous decision on sentence for Nichols, who was convicted of killing a judge and three others in a violent spree that began in a downtown Atlanta courthouse.
The judge ordered the jury to continue deliberating through Thursday afternoon and return Friday morning. He said he would order the jurors to return Saturday if no decision is reached by day's end.
Nichols was on trial for rape in 2005 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.