Shondell Davis’s son would be 26 now, but for the gunfire that took his life eight years ago in Roxbury.

The pain of his loss has never left her.

On Friday — three days before the anniversary of his death on April 24, 2009 — she had flashbacks of what she imagined to be the last moments of Johnny’s life, she said.

“It never goes away,’’ Davis said.

“It’s literally like hell. . . . You have triggers all the time. Some of them can be more severe than others. Some of them can stop you in your tracks.’’

The anniversary of Johnny Davis’s death, which Shondell Davis commemorated with a memorial celebration Saturday afternoon, comes as the city prepares to announce Tuesday the creation of four neighborhood-based trauma teams to provide immediate and long-term support and a new hotline for families and communities in crisis.

The teams — based in Dorchester, Roxbury, Jamaica Plain, and East Boston — will use a comprehensive approach to addressing the toll violence takes on people, officials said. A clinician and family advocate will work with staff at neighborhood health centers, hospitals, and community groups.

A 24-hour hotline run by the Justice Resource Institute’s SMART Team will be available for people in crisis.

“We want no one to go through a traumatic experience,’’ although that is not always possible, said Felix G. Arroyo, the city’s health and human services chief. “We just want them to know that they are not alone.’’

Mayor Martin J. Walsh and city health officials said the new trauma teams, launched after receiving community input over the summer, will offer a variety of recovery services to individuals and families. Officials are hoping the health centers and community groups they are partnering with — including the Bowdoin Street Health Center in Dorchester, Madison Park Development Corp. in Roxbury, and East Boston Neighborhood Health Center — will integrate with the teams.

The teams will be deployed within 72 hours of a violent incident, including a shooting, homicide, or a death of a child.

“These neighborhood trauma teams are going to be out in the community and connecting to residents immediately following an event,’’ said Catherine Fine, director of the division of violence prevention for the Boston Public Health Commission.

“What we really want residents to know is that they can access this service at any time,’’ she added. “And if that means six months after an incident takes place or two years or five years, we want them to know that is service is available to them.’’

In 2015, the city announced a similar effort, which stationed trauma recovery teams in health centers in Roxbury, Jamaica Plain, Dorchester, and Mattapan.

But Walsh said the health center teams were “not getting to the root of what we are trying to do.’’

“We are trying to fine-tune these [trauma teams] ... to break the cycle of violence and begin the healing,’’ he said.

Monica Cannon, a Roxbury antiviolence advocate, criticized the mayor for “regurgitating’’ the trauma teams, which she said lacked follow through.

“They had poor responses. There were multiple crime scenes where they didn’t show up,’’ she said. “There has to be follow-through.’’

She said she has been assisting the mother of a teenager who was shot at in February in the lobby of the Bruce C. Bolling Municipal Building, where the School Department is. The boy and his mother had been registering for school when gunfire erupted.

Cannon said she took to Facebook Live and contacted City Councilor Tito Jackson, who is running for mayor, to voice concerns about the lack of city support for the mother and son. In response, a trauma team reached out to the family, but after a few times, she said, the contacts stopped.

The young boy remains afraid to leave his house and his mother has difficulty sleeping, said Cannon, who keeps in touch with the family.

“This is a story that continues to happen with trauma response in the city,’’ she said.

Walsh said he does not disagree with Cannon: “Part of what we are doing here with these trauma teams is hearing from folks like Monica and other people who talk about recovery and healing,’’ he said.

The Rev. Richard “Doc’’ Conway regularly walks the streets of the Bowdoin-Geneva area and visits families affected by violence. He recalled this month visiting one family with two boys who had been shot, including one left paralyzed. Their 3-year-old sibling witnessed the shooting.

The boys’ two sisters continued to go to school every day but when they get home, they lock themselves in their room, Conway said.

“That is, in effect, trauma,’’ said Conway, who backs the move to have more trauma teams.

His church, St. Peter’s, has been offering monthly meetings after Masses to help neighborhood people deal with trauma. A social worker leads the meetings, mostly in Portuguese to help the Cape Verdean parishioners.

Meghan E. Irons can be reached at meghan.irons@globe.com. Follow her on Twitter @meghanirons.