A jury has told a judge that it is unable to reach a unanimous decision on a sentence in the case against a man who killed a judge and three other people in a shooting spree that started in a downtown Atlanta courthouse.

The judge is calling the jury back into the courtroom to decide the next step. The jury has deliberated for almost 20 hours.

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Prosecutors had asked the jury to sentence Brian Nichols to death. If the jury is unable to reach a unanimous decision, Georgia law requires the judge to decide whether to sentence the 37-year-old to life in prison with parole eligibility or life in prison without parole.

Nichols was convicted last month of murder and dozens of other counts in the 2005 killings.

Nichols 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.