A judge refused Monday to dismiss state charges against sniper suspect Lee Boyd Malvo (search) because of an alleged overlap with federal charges.

Fairfax Circuit Judge Jane Marum Roush also heard arguments on a change of venue motion but said she would rule later.

Malvo's lawyers had sought to have the Virginia charges thrown out because of a state law that forbids state prosecution when the federal government initiates a prosecution for the same crimes.

The state law is designed to bolster a defendant's double-jeopardy rights against multiple prosecutions.

Roush agreed with local prosecutors that the federal charges -- since dropped -- were carefully crafted to avoid such a conflict. She noted that the federal charges said nothing about the Oct. 14 shooting of FBI analyst Linda Franklin (search), for which Malvo is facing trial in Fairfax County.

"I'm required to follow Virginia law. The courts have on a reliably consistent basis ruled in cases like this that [the law] does not bar a second prosecution," she said.

Malvo, 18, and John Allen Muhammad (search), 42, have been linked to 20 shootings, including 13 deaths, in Virginia, Maryland, Georgia, Alabama, Louisiana and Washington, D.C. Prosecutors have said the three-week shooting spree was part of a scheme to extort $10 million from the government.

In another ruling, Roush allowed the defense to hire a handwriting analyst, at $2,500, to analyze writing on two notes found at crime scenes.

Malvo's lawyers also were seeking a change of venue, arguing that every resident of Fairfax County could be considered a victim of the sniper attacks under the prosecution's theory of the crime as an act of terrorism. The lawyers also allege that evidence leaked to the media has tainted the jury pool.

Prosecutors said they were confident an impartial jury could be found, and dismissed the notion that everyone in the county was a victim as an insult to the true victims and their families.

Roush said she would rule on the venue request within 30 days.