(KNOXVILLE) In the wake of Zaevion Dobson's death, one Knoxville mom is calling for an end to gang-related gun violence and is asking the entire community to step up.

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Devona Wilder lost her own son to gun violence four years ago.

Victor Michael Harris III was 19 when he was shot to death in what police call a gang-related shooting.

Wilder said her son's case went cold because no witnesses would speak in court. That's the reason for her plea to the community: If you see something, say something.

"My son was trying to do better for himself," Wilder told WBIR 10News Wednesday afternoon, recalling the period leading up to her son's death.

Life was looking up for her family, when on an afternoon in November 2011, death found its way to her doorstep.

"I heard my son screaming, 'Mama! Mama! Mama!' I was like, 'Oh, my God,'" she recalled, her voice heavy with emotion.

She ran outside her apartment at Arbor Place on South Hall of Fame Drive in Knoxville to find her son bleeding from multiple gunshot wounds. He later died.

"We saw all these people, and no one wants to say what's going on. Who can I trust?" Wilder said. "Everybody knows who killed my son, but no one wants to stand up and say nothing because they claim that they're scared."

The police report lists a number of witnesses who talked, but Wilder said none wanted to testify.

"It hurts, and all I have is pictures and memories," she said.

No closure.

Grieving mothers and law enforcement officials alike fight an uphill battle against a culture of 'no snitching.'

"If you see it, say it," she countered, "because when it's on your doorstep, you want the world to open their mouths. All us mothers want is just peace and justice."

The justice isn't solely for grieving families.

"In order for all this gang violence to stop, we have to do something about the past," she said. "We have to do something about these cold cases, where these boys are still running around here, committing more and more murders and nothing is done about it."

She saved her heaviest criticism for the gang's leaders.

"You got to think about all these older guys is putting these kids in these gangs," she said. "Why don't y'all stop putting them in there? Why don't y'all quit living off of these rap songs and these false dreams that y'all are selling these kids?

"Why don't y'all quit giving these kids these guns, putting them out there, sending them out, shortening their lives, shortening their futures and you just sitting back, laughing and thinking that it's OK? It's not OK."

She praised Zaevion Dobson for shielding his friends from gunfire last week in Lonsdale and said he doesn't have to be the community's only hero.

"You can be a hero, too. Stand up! Everyone is running around here, witnessing these murders and no one wants to say nothing about it. We all got to stand up for all these kids," she said.

She wants the young people of Knoxville to have a chance at the future - something that was taken away from both her son and her son's father, who was also a victim of gun violence.

"It's just a cycle," Wilder said. "It's just kids left behind, trying to feel their way through the world without their parents, and it's just sad. ...The community has to step in to stop all these senseless acts of death, all these senseless murders, all our babies. It has got to stop."

Her son was born on Christmas Day. He would've turned 24 this year.

"I just sit and I imagine what he could've been," Wilder said.

She said she plans on throwing him a birthday party, so her two young daughters can get to know their brother who was killed when they were just babies.