Lee Boyd Malvo was 17 when he was arrested for the attacks that killed 10 people in the Washington area in 2002.
A US federal judge on Friday threw out the life terms for a man sentenced for his role in a deadly three-week shooting spree in 2002 that terrorised the Washington area.
US District Judge Raymond Jackson in Virginia ruled that Lee Boyd Malvo deserved another sentencing hearing because the US Supreme Court has ruled that mandatory life sentences for minors are unconstitutional.
Malvo, who was 17 when he was arrested over the killings, was serving two life sentences on two counts of capital murder in Virginia. They have now been vacated.
The series of sniper shootings in 2002 paralysed the Washington area. Ten people were killed and three wounded in Virginia, Maryland and the US capital.
Malvo was also sentenced to life in prison in Maryland.
Malvo's partner in the shooting spree, John Allen Mohammad, was sentenced to death and executed in 2009.
During the October 2-22, 2002 shooting spree, Mohammad, a skilled marksman, and Malvo picked off victims with a high-powered sniper rifle seemingly at will.
The random killings terrified an area still living in dread of a repeat of the September 11, 2001 terror attacks and deadly anthrax mailings a year earlier.
People would squat down by their cars as they pumped gas, run from their vehicles into work, or just stay home.
Mohammad, who was a father-like figure to Malvo, killed each of his victims with a single bullet fired from a distance, and was apprehended after an exhaustive manhunt by federal and local police.
Mohammad's motive was unclear, although his second ex-wife alleged he intended to shoot her and reclaim custody of their three children.