CHESAPEAKE, Va. (AP) — Sniper supsect Lee Boyd Malvo pleaded not guilty to murder Monday as his trial was opening in the slaying of an FBI analyst shot to death during the three-week sniper spree in the Washington, D.C., area last fall.

The 18-year-old responded, "Not guilty," in a clear voice each time when asked for his plea to two counts of capital murder and to one count of using a firearm in a felony.

He politely responded, "Yes, ma'am," when the judge asked if he was ready for trial.

Defense attorney Craig Cooley told Circuit Judge Jane Marum Roush that he plans to present a defense of innocent by reason of insanity.

Before the arraignment, defense attorneys asked Roush to dismiss one of the capital murder charges, which alleges that Malvo committed an act of terrorism when he allegedly shot Linda Franklin outside a Home Depot in northern Virginia.

Defense attorney Mark Petrovich argued that the grand jury's indictment was tainted. Petrovich noted that the judge had moved trials about 200 miles to Chesapeake partly because northern Virginia residents were terrorized by the sniper spree. He said the grand jury also should have been moved.

The judge denied the defense request, saying, "I never heard of such a thing as a change of venue for a grand jury."

Defense lawyers plan to argue that Malvo was so brainwashed by fellow suspect John Allen Muhammad, 42, that he either did not know what he was doing or could not control himself.

Malvo and Muhammad, whose trial entered its fourth week of testimony Monday in neighboring Virginia Beach, are being tried in two different killings. Both face the possibility of the death penalty if convicted.

Authorities have said Malvo has admitted committing many of the shootings, and investigators have testified in Muhammad's trial that Malvo's fingerprints were on the .223-caliber rifle used in the attacks, and that his DNA or fingerprints were found on evidence from several of the scenes.