Lee Boyd Malvo was 17 when he and his mentor, John Allen Muhammad, then 41, shot people in Virginia, Maryland and Washington as they pumped gas, loaded packages into their cars and went about their everyday business during a three-week period in 2002.
Muhammad was sentenced to death and was executed in Virginia in 2009.
A jury convicted Malvo of capital murder for killing FBI analyst Linda Franklin, who was shot in the head outside a Home Depot store, but spared him the death penalty. Malvo later struck plea deals in other cases in Virginia and Maryland. He ultimately received four life sentences in Virginia and six in Maryland.
Malvo's lawyer Craig Cooley on Tuesday urged the 4th U.S. Circuit Court of Appeals to uphold a ruling by a federal judge who last year ordered new sentencing hearings in Virginia under a U.S. Supreme Court ruling that found mandatory life-without-parole sentences for juveniles unconstitutional. A 2016 Supreme Court ruling made the decision retroactive, extending it to people like Malvo who were already sentenced before the court found such punishments unconstitutional.
Cooley said the judge who presided at Malvo's trial gave the jury only two choices in recommending a sentence for Malvo - life in prison without the possibility of parole or the death penalty - with no option for a lesser sentence.
Jurors, Cooley said, "opted to go as low as they could under the structure they were given on that date." He said the jury's unanimous decision to give him life instead of the death penalty indicates "they may have gone lower if they knew they could have."
But Deputy Solicitor General Matthew McGuire said the trial judge had discretion to reduce the jury's recommendation, but did not do so. He said the Supreme Court ruling does not apply to states that don't have mandatory life-without-parole sentences.
The three-judge panel questioned Cooley extensively about Malvo's plea deal with prosecutors in which he agreed to plead guilty and receive a sentence of life in exchange for prosecutors dropping some charges and removing the death penalty as a possible sentence.
"How do you get around the plea agreement - the finality of plea agreements?" Judge Paul Niemeyer asked Cooley.
Cooley said Malvo agreed to "what is now an illegal sentence, an unconstitutional sentence."
After the hearing, Cooley told reporters that Malvo is simply asking for the opportunity to argue for a new sentence. He noted that Malvo still faces life sentences in Maryland, where a judge ruled last year that he will not get new sentencing hearings.
"In the end, it doesn't mean that he's walking out of prison," Cooley said.
The court did not indicate when it will rule.
Other former teen offenders still are awaiting a chance at resentencing in states and counties that have been slow to address the court ruling, an earlier Associated Press investigation found. In Michigan, for example, prosecutors are seeking new no-parole sentences for nearly two-thirds of 363 juvenile lifers. Those cases are on hold until the Michigan Supreme Court determines whether judges or juries should decide the fate of those inmates. The court heard arguments in October.
Some courts are applying the 2016 ruling to those whose life-without-parole sentences weren't mandatory, like Malvo's, or were negotiated as part of a plea deal.
Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.