On the sixth floor of the federal courthouse in Alexandria, jurors this week wrestled with the weighty question of whether to execute two convicted street gang members who killed a government witness.

But the divided jury also was tackling a much broader problem: how to get through to the violent Mara Salvatrucha gang, which has become the dominant street gang in Northern Virginia.

"We needed to send a hard message to MS-13 that their system of justice cannot be tolerated," juror William Atwood said yesterday.

Seven of the 12 jurors thought a death sentence for Ismael Cisneros, 26, and Oscar A. Grande, 22, could deter teenagers from joining Mara Salvatrucha, or MS-13, Atwood said.

In the end, without a unanimous vote for the death penalty, the two men will be sentenced automatically to life in prison without the possibility of release for the murder of Brenda Paz, 17. But 11 jurors found a different way to send a message: They wrote an unusual paragraph into their verdict form expressing the hope that Grande and Cisneros use their decades in jail to counsel Latino youths on the dangers of gangs.

"We felt it would be impossible to bring Brenda Paz back to life," said one juror, who spoke on condition of anonymity because of the nature of the charges. "Some of us thought that if anything good could come out of this, it could be a message to the youth to not get involved in gangs."

Jury foreman Henry Wayne Gardner said jurors expected Northern Virginia schools and political leaders to take action as well. "Basic intervention needs to take place before these kids join a gang," he said. "There needs to be alternatives for young people at ages 10 through 14. They need to be involved in wholesome activities."

Paz was killed just weeks after she left the federal Witness Protection Program because she cooperated with authorities in investigations of gangs in Virginia and across the country, according to testimony. Her body, stabbed multiple times, was found by a fisherman on the banks of the Shenandoah River in July 2003. She was 16 weeks pregnant.

The jury convicted Cisneros and Grande on five counts, including conspiracy to retaliate against a federal witness and killing a person aiding a federal investigation. The jury acquitted two other MS-13 members in Paz's death: Denis Rivera, 21, who was accused of ordering her slaying from jail, and Oscar Garcia-Orellana, 32.

The jurors, who included defense contractors, a nonprofit worker and two lawyers, said yesterday that prosecutors presented overwhelming evidence that Grande and Cisneros stabbed Paz after luring her on the pretense of a fishing trip. "There was no question in anyone's mind about their guilt," Gardner said.

But when the same jury reconvened last Thursday to decide on sentences, the issues grew more complex. One group of jurors thought from the start that death was appropriate, several jurors said.

Other jurors expressed concerns about the death penalty, which has been controversial in recent years as some death row inmates have been exonerated because of DNA and other evidence. "I believe the death penalty is not administered fairly in this country, that it discriminates against people of color," Gardner said.

At some point, although the debate was collegial, it became clear the two sides would not budge. But then on Monday, one juror suggested a way to make a difference in the gang problem. He pointed out that Cisneros had several times expressed an interest in working with kids on the dangers of gangs, several other jurors said.

Nine jurors wrote as a mitigating factor that Cisneros has "made repeated offers to speak out to youth against gang involvement." Mitigating factors are explanations that would tend to argue against a death sentence. Eleven jurors wrote that life in prison for both Cisneros and Grande would give them "the opportunity to reach out to Hispanic youth on the dangers of gangs."

In doing so, the jurors realized that neither they nor the court could compel the men to follow the jury's wishes.

"It's more of a hope that they will take advantage of the opportunity to give some meaning to their lives, because right now their lives had few redeeming qualities," said the juror who spoke on condition of anonymity.

Atwood did not vote for either mitigating factor. "I call it wishful thinking," he said.

But Jim Clark, an attorney for Cisneros, said Cisneros has already started counseling Hispanic youths in prison about the dangers of gangs.

"He is very serious about trying to help people avoid doing the things that he has done," Clark said. "His life is committed to that."

Brenda Paz was killed by members of MS-13 because she provided evidence of crimes by the gang.