Philly wants to bring back a version of an old strategy to fight gun violence. Specifics are pending.

With Philadelphia experiencing a steady uptick in homicides and shootings, Mayor Jim Kenney has pledged to roll out a gun-violence reduction strategy generally known as group violence intervention, a collaborative effort among a variety of agencies that has worked in other cities.

The idea — one of several initiatives in a sprawling plan to treat violence as a public health issue — is for law enforcement to identify a small population most likely to shoot or be shot, then continuously meet with those people to implore them to put down the guns and talk through conflicts, offer them social services, and later, if necessary, arrest and charge those suspected of shooting someone. Some models suggest punishing a shooter’s associates as well.

Six years ago, Philadelphia tried such an approach, dubbed Focused Deterrence. Variations have also been implemented in cities including Boston and Indianapolis. In Oakland, Calif., shootings and homicides have dropped nearly 50% since 2012, when the city began use of a similar policing strategy it calls Ceasefire.

The Rev. Michael McBride, an Oakland pastor, said it took nearly two years of discussions — and a steady stream of gun violence — for residents to successfully press city officials to deploy that cohesive, collaborative strategy instead of working on well-meaning but sometimes separate initiatives.

“Everybody’s got to ask themselves,” McBride said in an interview last month, “ ‘With our best efforts, why is violence up?’ ”

The particulars in Philadelphia’s plan are still very much in development, according to interviews with more than a dozen city officials and community members. Among the unknowns: How will potential shooters be identified? How often will they be confronted? And how will enforcement work in a city that has been seeking to reduce the footprint of its criminal justice system?

City officials say that everyone working on the strategy — expected to debut in West Philadelphia in the spring — wants to get it right, and that representatives from agencies including the Office of Violence Prevention, the Police Department, and the District Attorney’s Office are meeting regularly to work through details.

“From the research side, it’s a shame that we as a city can’t move faster, because people are dying every day,” said Caterina Roman, a Temple University criminal justice professor who has spoken to stakeholders in the initiative. “But there has to be a lot of careful thought put into this, [to] make sure there is agreement and understanding that the partners truly are at the table.”

Focused Deterrence was first used in South Philadelphia in 2013. Police and prosecutors identified people they believed were most likely to be involved in shootings or associated with those who committed them, then staged “call-ins” urging suspected crew members — many on probation for other offenses — to stop the violence.

Those called in were offered services, such as job training and other support. But they also were told that if anyone pulled a trigger, their entire crew would suffer: higher bails, crackdowns on probation or child support, even the potential for Peco to cut off bootlegged electricity in suspected gang houses.

“All of us are here today because we appreciate that the violence must end in our community," Common Pleas Court Judge Sandy L. V. Byrd told participants in a City Hall courtroom in 2013. “We are here because we know that you and the people in your group are the individuals most likely to kill another human being or be killed. Young men: The community needs you alive, out of prison, free, and making a contribution to your community.”

Then-Police Commissioner Charles Ramsey was more blunt.

“I’ve been in this business more than 40 years and I’m tired of picking up bodies off the streets of our city,” Ramsey said. “People in these communities cannot let their kids go out and play. You’ve got to walk around looking over your shoulder afraid somebody’s gonna pop you. At some point in time it’s gotta stop. So put down the guns.”

The program lasted two years, with encouraging results: A study by Roman and several colleagues said shootings in targeted neighborhoods declined by 35%.

But the strategy fizzled out over time, with some involved blaming a lack of funding or institutional support. Many now also acknowledge that the approach became overly centered on law enforcement, and essentially abandoned the idea of providing social services as a counterweight.

“It turned into over-policing, to be quite honest,” said Movita Johnson-Harrell, a West Philadelphia activist whose father, brother, and son were killed by gun violence and who became a key advocate of Focused Deterrence and efforts to revive it. “It turned into stop-and-frisk.” (Now a state representative, Johnson-Harrell was charged this week in an unrelated corruption case.)

In addition to the success in Oakland, group violence intervention has led to declines in gun violence of more than 30% in Indianapolis, Boston, and Cincinnati, according to the National Network for Safe Communities, a research center at John Jay College of Criminal Justice in New York City. Staffers there, including director David Kennedy, have been involved in Philadelphia’s recent planning efforts.

It was not immediately clear how or if the charges against Johnson-Harrell might impact her involvement in the efforts. But either way, many others are expected to participate.

Three top city officials — Managing Director Brian Abernathy and Vanessa Garrett-Harley and Theron Pride, who oversee violence prevention efforts — said they are committed to the principles of the strategy and believe it must emphasize social services this time, rather than punishment. They don’t plan to call it Focused Deterrence.

“We are trying to think about: ‘Who can we help?’ ” Pride said. “People care deeply about this issue, and it’s the care that is driving this, and the enforcement that’s needed is going to also be coupled with services and support.”

They said a target area in West Philadelphia is still being defined. They did not specify how people would be identified as likely shooters or victims, or provide names of community members who may be involved in the effort.

The city also is still searching for a permanent police commissioner. Abernathy said he was not concerned about the strategy conflicting with the views of a new top cop.

District Attorney Larry Krasner said his office is high on a strategy used in Los Angeles, known as GRYD, which, among other things, increases youth access to parks and recreation centers at night as an alternative to the street. Krasner said attempts in Philadelphia in recent years to restrict the ability to throw block parties for fear of violence, or use noise machines to deter after-hours loitering or vandalism at parks, were “the exact opposite” of GRYD’s approach.

There are other philosophical questions. Since taking office, Krasner has been outspoken about the need to reduce the number of people on probation and shorten their terms, and he has criticized some so-called risk assessment tools, which seek to use data to determine a person’s risk of committing further crimes. Critics say the tools perpetuate racial inequities.

Those positions seem to collide with the notion of using information to identify people from largely poor, minority neighborhoods who may commit a crime in the future. Krasner said police intelligence and court documents can provide clues for a responsible analysis of links between potential offenders — identifying codefendants in one case who may pay each other’s bail in another, for example.

But he said that “a bunch of details” still have to be resolved, and that efforts to identify crew members “will be meaningless if they sweep too many people onto them for no particularly good reason.”

Common Pleas Court Judge Benjamin Lerner, who was involved in the original Focused Deterrence, said no one from the city has asked him about potential pitfalls or solutions. In his view, the organizers of the strategy “can’t underestimate the importance” of involving a large group of well-trained and active community members to bridge the gap between city officials and suspected offenders.

McBride, the pastor in Oakland, agrees that community buy-in is essential for another reason: to “keep the political chiefs from scuttling [it].” A sustained community push in Oakland has allowed its Ceasefire strategy to outlast several mayors and police chiefs, he said.

McBride acknowledges that every city will have its own challenges developing and maintaining a successful approach. But he believes group violence intervention can work anywhere, because he has seen the impact firsthand.

“The principles of the work have translated,” he said.