Whether at a church meeting or on a radio talk show, when U.S. Attorney Ronald C. Machen Jr. speaks in public, the conversation invariably shifts to two topics: violent crime and crooked politicians.

Machen doesn’t shy away from talking about his office’s recent string of charges and convictions in the two courthouses where he directs prosecutions: U.S. District Court and D.C. Superior Court. But he is just as proud of a less public pursuit as well: his effort to reduce crime rates among District teenagers.

On Thursday, more than 500 young people from across the District, ages 8 to 18, are expected to converge at Friendship Collegiate Academy in Northeast Washington.

“Yes, cracking down on political corruption and violent crime is important. But our youth of this city, and what this office is doing with them, is also important,” Machen said Wednesday.

The early-summer gathering, dubbed “Breaking the Silence on Youth Violence,” is being held for the third time since Machen became the District’s top law enforcer in 2010. The free event — featuring lunch, live music, a step team and even Marcus Canty, a finalist from the TV talent competition show “X Factor” — is growing in popularity among local teenagers. Last year the event drew only 330 youths, organizers said.

“We’re not going to save everybody, but if we can save one child, then it’s worth it,” Machen said.

Machen has several goals: He wants to celebrate young people who are excelling in school and have no criminal record. He also wants to educate teenagers on some of the biggest issues facing them: truancy, sexual assault, bullying, and a popular new drug known as K2 or Spice — a synthetic substitute for marijuana.

During the program, the teenagers will be divided by gender to talk about sexual assaults and how they can avoid such situations.

According to D.C. police statistics, 96 sex assault cases this year have involved victims younger than 18. Last year, D.C. police handled 225 sex assault cases involving juvenile victims.

Members of the D.C. police, the FBI and the D.C. Rape Crisis Center will speak at the event. Also scheduled to speak about their life experiences are ex-offenders and former gang members.

Attendees will include those who have been arrested and are under supervision by the Department of Youth Rehabilitation Services. Some of them have been hired as unpaid summer interns in the U.S. attorney’s office.

D’Anthony Hedgespeth, 13, who will be entering his freshman year at Kipp DC College Preparatory in Southeast, attended the forum last year. He said, “It teaches you a lot of about how life isn’t going to be easy, including peer pressure, and how you have to get around it and continue to do what you’re supposed to do.”