Valerie Dixon spent many sleepless nights searching for the right words to deliver to a courtroom full of the city's toughest criminals -- men fresh out of jail, men in gangs, men like the one who killed her son.

What could a mother still grieving after nine years possibly say that would convince them to give up their guns?

"There were some nights I prayed about it, I cried about it, because it's so painful to think about my son's death," she said. "I wanted to make sure God would give me the words that would pierce their hearts."

She decided to read them a document she had not touched in nine years: her son's autopsy report.

She talked about the way the bullets, four of them, tore through Robert Dixon's otherwise healthy, 22-year-old body. She talked about a mother's enduring pain and lingering questions.

When she looked out at the men from behind a podium, past her own tears, she noticed some of their eyes had welled up, too.

Ms. Dixon gave her emotional testimony during two Tuesday gatherings in the federal courthouse, Downtown, that marked the start of a long-awaited anti-violence program, the Pittsburgh Initiative to Reduce Crime, aimed to diminish the city's homicide rate.

The "call-in" sessions fell on a day when detectives were investigating the 26th and 27th killings of the year -- the Sunday shooting of an East Hills mother and the stabbing of a woman whose decomposing body was discovered Tuesday outside Langley High School.

Homicides fell 45.8 percent, from 72 in 2008 to 39 last year, but Mayor Luke Ravenstahl said the need for the strategy remains.

"People are still shooting, people are still dying," Mr. Ravenstahl said after the sessions, which he observed but were closed to reporters. "We delivered a message that enough is enough. Put the guns down. This has to end."

About 55 members of the city's 37 violent street gangs sat in a courtroom gallery and listened as their neighbors told them violence is no longer tolerable, law enforcement promised swift punishment for future crime, and service-providers offered an array of help. But they must stop shooting.

"Even if they just put the guns down, that's all we ask," Ms. Dixon said.

Police Chief Nate Harper described the young men sitting on one side of the courtroom as "influential" members of the city's gangs, selected through police intelligence and summoned there through a letter. Their probation and parole officers would be notified if they failed to show up.

The sessions were held amid heightened security. Groups of police officers gathered outside the federal courthouse, on hand in case of a feud, the chief said. But the day was without incident.

None of the men are strangers to police. Some could not attend because they're still in jail, acting U.S. Attorney Robert S. Cessar said. They were chosen because "they're people that have a voice in those associations," who, police hope, will return to the streets and relay the message to fellow group members.

Beside them in the room were community members. Social workers sat in the jury box. Before them were members of law enforcement, who told them what might await them if the violence doesn't end. After the next homicide, they'll all come under increased scrutiny -- not just for the shooting, but for every crime in which they take part.

Mr. Cessar said they seemed surprised to learn of potential federal penalties, including pre-trial detention and years in a prison far away from their friends and loved ones.

Members of One Vision One Life and Pittsburgh Community Services Inc., nonprofit nonviolence groups with which the city has contracted for the program, spoke next about the job training, drug treatment, counseling, educational help and other opportunities within their reach. Then, the men heard from "community voices," people such as Ms. Dixon, another mourning mother, Geraldine Massey, and former gang member Brandon Humphrey, who now owns a cleaning franchise.

Their message was simple and direct: The violence needs to stop, and there are ways out.

"What happened here was electrifying," said the program's architect, David Kennedy, a professor and the director of the Center for Crime Prevention and Control at John Jay College of Criminal Justice in New York. "I watched the faces of the invited guests, and when I see them nodding along in agreement with what law enforcement, the community folks and social service providers are saying, I know we've gotten someplace special, and that's what just happened. ... These guys, who many people reject as lost, sociopaths, psychopaths, sat there and they nodded their heads in agreement because it's the truth and said that directly, almost nobody disagrees with it."

As the call-ins drew to a close, police and prosecutors left the room, leaving outreach workers and case managers behind to hear feedback from the gang members. They handed them a card with a "PIRC hotline" phone number and the message, "The killing must stop! Change begins with you!"

While some clearly showed no interest, many seemed to be listening, said Khalif Ali of Pittsburgh Community Services.

"Some took more than one card," he said. A couple asked if they could call the number immediately.

Then, they left.

Officials expect change by the next call-in, which hasn't been scheduled.

"We sometimes see results tomorrow," Mr. Kennedy said. "They get to control what happens. They're on notice now."

Ms. Dixon, too, was hopeful.

"When I walked out, I said, 'Good luck to all of you,' " she said. "And they said, 'Thank you.' "

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