Do gang sweeps reduce violence?

Gang sweeps — like the one conducted at a Boston housing development Thursday — can be effective for quickly quelling sudden spikes in crime, but law enforcement officials and analysts are divided on whether they are effective in combating gang violence in the long-term.

“The gang sweep is a tool, but if that’s the only tool you have in your toolbox, you’re going to fail,” said Richard Valdemar, who spent more than 30 years battling gangs as a member of the Los Angeles County Sheriff’s Department.

“There’s always going to be resurgence.”

Federal authorities conducted one such raid at the Lenox Street Housing Development in Roxbury Thursday, arresting 19 people on gun and drugs charges. It follows another high-profile raid in January targeting MS-13 gang members throughout the North Shore.

The January raid on MS-13 was one of dozens targeting the gang over the last 20 years, when the group first appeared in Greater Boston. After the latest raid, officials expressed concern about the need to stop the cycle of younger gang members filling the void when older gang members are arrested.

US Attorney Carmen M. Ortiz used a press conference at the courthouse to plead for community members to do more to steer young people away from becoming the next generation of MS-13 members.

“We can’t do it alone in terms of just prosecuting cases,” Ortiz said. “We need to be involved, working with law enforcement, working with the schools, working with the parents, working with the community, to try and provide them with assistance and resources to hopefully veer them away from taking this path, and providing them with real legitimate alternatives.”

Jason Ziedenberg, a research and policy director at the Justice Policy Institute in Washington, has studied the failure of gang suppression tactics and said law enforcement sweeps can be counterproductive because they sometimes ensnare vulnerable youth in the criminal justice system when educational or awareness programs might have been more appropriate.

“What we know is that when we have these suppression tactics, it focuses on broad groups of people, and it doesn’t help them leave the gang and it’s not a structure for them to leave,” said Ziedenberg, who a decade ago co-authored a policy report, “Gang Wars: The Failure of Enforcement Tactics and the Need for Effective Public Safety Strategies.”

Ziedenberg said officials realized long ago that “We can’t arrest our way out of the problem.”

“After the sweep, the fundamental challenges in the neighborhood haven’t been addressed,” he said. “You can have a sweep one year, a sweep the next year . . . but what, fundamentally, has been done differently after the sweep has left?”

Local law enforcement officials, such as Coppinger in Lynn, agreed with those who call for more gang prevention programs, saying his community went without such programs for years because of budget cuts.

“It’s a big circle; you’ve got to include the whole thing,” he said.

He added, however, that “Some of these kids are still attracted to gangs, they glorify them, and it’s a tough challenge to combat. We’re going to have to keep an eye on them.”

Because of that, predawn raids — which often yield high-profile news coverage — have become a go-to strategy for law enforcement officials when a community sees a spike in crime or notices a gang starting to take hold. Law enforcement officials say the raids are especially effective when they involve federal law agencies that can levy charges with more serious punishments than state authorities can.

Bill McGonagle, administrator of the Boston Housing Authority, recalls a sweep of gang members in Mission Hill in the 1980s. Residents applauded federal agents as they arrested people who had been terrorizing the neighborhood. The sweep not only was good publicity for law enforcement agencies, but also took bad guys off the street, McGonagle said.

McGonagle said he was not qualified to speak about long-term solutions to gang violence, noting that affordable housing is a critical component to helping people avoid a life of crime, but, he said, “if we have bad guys in our developments, and they want to come in after them, I’m OK with that.”

Any public housing resident convicted of a crime faces possible eviction.

A Globe review of several raids shows most of those arrested on federal charges spend some time in prison.

After a 2006 sweep by FBI agents and local police officers of the Bromley-Heath housing complex in Jamaica Plain, all but one of the 18 people arrested on federal charges were convicted, and most were sentenced to more than five years in prison, according to the review of the cases. Some received 10-year prison terms.

A review of the 2013 sweep in Boston’s Bowdoin-Geneva neighborhood in Dorchester shows that all but three of the 30 people arrested were convicted, and most were sentenced to at least five years in prison. Some, like Alexis Hidalgo, the leader of one gang from Hendry Street, were sentenced to 12 years.

And a review of the 2010 sweeps in Lynn shows that all 35 people convicted in federal court served prison sentences. Some were sentenced to more than 12 years in prison. Lynn police data also shows that gang-related shootings declined during the summer of the 2010 raids to 5, compared to 27 the previous summer. There were 4 people shot the summer of 2010, compared to 13 the previous summer.

Meanwhile, most of the 50-plus people who were targeted in the June 2015 sweep of Columbia Point Dawgs gang members in Boston remain jailed while their cases make their way through the federal court.

David Kennedy, the director of the National Network for Safe Communities at the John Jay College of Criminal Justice in New York, said that law enforcement sweeps remain the best tool for confronting well-organized gangs such as MS-13.

“That’s when you’ve got a real problem, and a really focused, meaningful law enforcement operation on that gang, that group, can make a lasting difference,” he said.

Kennedy said that cities need to pair law enforcement strategies with prevention efforts, but said it is not uncommon for a city like Boston to see, every few years, a gang “rise to a level where it draws attention to itself. And then the authorities move in.”

“Nobody, anywhere, has been able to make really meaningful lasting reductions in violence without there being an important law enforcement component. Everyone would love to figure out how to do it, but so far nobody has.”

Milton J. Valencia can be reached at milton.valencia@globe.com. Follow him on Twitter @MiltonValencia.