A US judge has sentenced Washington sniper John Allen Muhammad to death for his role in the October 2002 killings.
The judge confirmed the death sentence on Muhammad
The formal sentencing in Manassas, Virginia, came four months after a jury found the 42-year-old Army veteran guilty and recommended his execution.
Circuit Judge LeRoy Millette Jr said Muhammad's actions were "so vile that they were almost beyond comprehension".
Muhammad and his accomplice, Lee Boyd Malvo, shot dead 10 people in a three-week killing spree.
Their actions spread terror throughout the Washington area, leaving people afraid to go shopping or visit petrol stations because of the risk of attack.
The shootings were carried out from the back of a specially converted car.
Judge Millette set the date of Muhammad's execution for 14 October, but correspondents say it is likely to be postponed to allow appeals.
If the death sentence is ultimately upheld, Muhammad will have to decide whether it is by lethal injection or by the electric chair.
Muhammad was convicted of the killing of Dean Meyers on 9 October 2002 and of murdering "at least one other person".
In court for the sentencing, he continued to deny that he was involved in the killings.
"Just like I said at the beginning, I had nothing to do with this, and I'll say again, I had nothing to do with this," he said.
Defence lawyers acting for Muhammad had argued for leniency, saying that his lack of a previous criminal background and the effect of an execution on his children should be taken into account.
Muhammad's accomplice, Malvo, was tried in a separate case and is due to be formally sentenced on Wednesday in the nearby town of Chesapeake.
The jury recommended that Malvo, 18, should face life in prison without parole.
The judge has no power to impose a harsher penalty, but Malvo could still be sentenced to death for other killings.