The state of Virginia urged a federal judge in court papers filed Wednesday to reject Lee Boyd Malvo’s attempt to challenge his many life-without-parole sentences in connection with a series of random, sniper-style shootings that terrorized the D.C. area a decade ago.

Va. Senior Assistant Attorney General Donald E. Jeffrey III wrote in the filings that state law does not impose a mandatory life-without-parole sentence, and thus Malvo’s sentences could not be considered unconstitutional under the Miller v. Alabama ruling.

Malvo’s lawyers in June had challenged Malvo’s sentences under that decision, which held that mandatory life-without-parole sentences effectively constituted cruel and unusual punishment for children, but judges could still impose the stiff penalty if they took mitigating circumstances into consideration.

Jeffrey also argued in the filings that the Miller decision should not be applied retroactively, and that even if it were to apply to some of Malvo’s sentences, it clearly did not to life-without-parole terms he received in Maryland and in Spotsylvania County, Va.

“Malvo’s six Maryland sentences and his agreed life-without-parole-sentences for Attempted Capital Murder in Spotsylvania County plainly do not violate Miller, because none of them carried a ‘mandatory’ sentence of ‘life without parole,’” Jeffrey wrote. “Even if Miller properly could be applied in this case, doing so would be a purely academic exercise, amounting to an advisory opinion.”

Malvo and John Allen Muhammad ambushed 13 people, killing 10 of them, in the D.C. area over 21 days in October 2002. After the two were caught, they were tied to at least 11 more shootings from Washington state to Alabama, five of them fatal.

Muhammad was sentenced to death and executed in 2009. Malvo remains incarcerated at Red Onion State Prison in Wise County, Va.