CHESAPEAKE, Va. - Jurors weighing the fate of Lee Boyd Malvo - the teen-ager accused in a shooting rampage that left 10 dead and sent waves of terror around the nation's capital last fall - did not reach a verdict yesterday after deliberating seven hours on the intricacies of a complex insanity defense.

The jury of eight women and four men will resume its duties this morning in a case that has presented two vastly different pictures of Malvo.

The first, presented by the prosecution, alleges him to be a cunning, manipulative killer with no mental dysfunction. The other, from the defense, paints him as a wayward child from the Caribbean who was brainwashed by an older, more sophisticated man intent on unleashing havoc and a new world order.

Malvo is charged with two counts of capital murder in the fatal shooting of FBI analyst Linda Franklin, 47, of Arlington, Va., in the parking lot of a Home Depot store near Falls Church, Va., on Oct. 14, 2002.

Yesterday, before going home, jurors sent Circuit Judge Jane Marum Roush three questions that shed a small ray of light on the issues with which they were grappling.

The jury, which must find that Malvo acted with "malice" to convict him of capital or first-degree murder, had questions about the meaning of the word and its relevance to the legal definition of insanity.

The jury's interpretation of insanity - essentially defined in Virginia as a person's inability to tell right from wrong - is a critical factor that will likely decide the outcome of the five-week trial and whether Malvo will be dealt a death sentence.

Some legal experts say the insanity plea might be eroded by evidence that Malvo, 18, sometimes felt doubts about the murderous mission he embarked upon with his accomplice, John Allen Muhammad.

His feelings of occasional guilt, which he confided to mental health experts, would seem to undermine the defense contention that the teen-ager did not know right from wrong while in the midst of the sniper killings.

'Conflicted' feelings

Prosecutors point to several pieces of testimony they say show cognizance of right and wrong and therefore fly in the face of Malvo's insanity defense.

Among them is a statement Malvo made that he felt "conflicted" about shooting a 13-year-old boy at a Bowie middle school; a letter he wrote two months before the shootings began that was described as a "cry for help"; and letters he wrote to a fellow inmate in jail that showed him perhaps more cunning than defense attorneys have led the jury to believe.

"The inconsistencies with the defense theory, which were evident during the defense's own presentation, are reasons why the jury is likely to reject the insanity defense," said Steven D. Benjamin, president-elect of the Virginia Association of Criminal Defense Lawyers.

But Benjamin said that the defense can still have hope if the jury does not find Malvo insane, adding that he believes Malvo's lawyers never really expected to win an acquittal based on insanity.

Virginia juries don't buy excuses from serial killers, Benjamin said, but by waging an insanity defense, attorneys were able to introduce all sorts of evidence that normally wouldn't come into play until sentencing.

Jurors heard about Malvo's troubled and itinerant childhood, about how he was beaten often and frequently moved among homes and schools.

They heard how he was an obedient boy who wanted to go into the Air Force and become a pilot until he met Muhammad and his life changed.

Malvo's plans were set aside as Muhammad, 42, put him on a strict diet and exercise regimen and filled his head with racist and anti-American propaganda.

The intense indoctrination, the defense argues, made it impossible for the youth to tell right from wrong and thus qualifies him as legally insane.