The Fairfax County prosecutor intends to persuade a jury to recommend a death sentence for sniper suspect Lee Boyd Malvo by showing that last fall's string of lethal shootings was vile and depraved and that Malvo would pose a danger if he isn't executed.

The filings by Fairfax Commonwealth's Attorney Robert F. Horan Jr., made public yesterday, were his first response to a sheaf of motions filed by Malvo's lawyers this month. The defense team made requests for its own experts and investigators, made demands on the prosecutor to provide information, and asked Fairfax Circuit Court Judge Jane Marum Roush to prevent Horan from discussing sniper shootings that have not been tried.

Malvo, 18, and John Allen Muhammad, 42, face capital murder charges in the Washington area shootings that left 10 dead and three wounded last fall. Muhammad is being prosecuted in Prince William County and faces an Oct. 14 trial date. Malvo's trial is set for Nov. 10.

Malvo is charged in Fairfax with fatally shooting Linda Franklin, 47, in Seven Corners on Oct. 14. In addition to the 12 other area shootings, he and Muhammad are suspected or charged in several shootings across the country.

Although the Virginia trials will be the first for Malvo and Muhammad, Horan plans to use evidence from other shootings in the penalty phase of the case, if Malvo is convicted. Horan wrote that Virginia courts have approved the use of "unadjudicated conduct" in the sentencing phase, and he asked Roush to give him until July 1 to disclose which shootings he plans to use.

To obtain a death sentence, a prosecutor must prove that a killing was particularly vile or that the defendant poses a future danger. "The Commonwealth intends to prove both," Horan wrote.

"It will rely on depravity of mind and the circumstances of the crime to prove 'vileness,' " Horan wrote, "and it will prove 'future dangerousness' by the circumstances of the crime and the substantial number of homicides, whether adjudicated or unadjudicated, in which this defendant has been involved."

Horan said he did not oppose a defense request for a mental health expert.