After almost two years of surveillance and undercover work, an army of more than 300 law enforcement officers set out at dawn Thursday to crush two of Boston’s most violent street gangs, arresting 27 longtime criminals on federal narcotics and firearm charges that prosecutors hope will end what had become a revolving door of arrests and short prison terms.
The raid came as welcome relief to residents on Woodward Avenue in Roxbury and in the Bowdoin-Geneva section of Dorchester, where authorities said the two gangs have been the driving force behind more than 60 shootings and six homicides in the last six years.
“I’m glad they got them off the streets,” said Victor Arrington, a retired firefighter who lives in Bowdoin-Geneva.
The effort by more than a dozen local and federal agencies took tenacity and perseverance, law enforcement officials said, and they hope the number of arrests and charges that carry lifetime prison sentences will be a warning to other gangs and help stem the violence that surges each summer.
“This will make a difference,” Police Commissioner Edward F. Davis III said at a press conference at the US attorney’s office. “I’m anticipating a much quieter summer because of the work that occurred this winter.”
Many of the suspects have plagued the two neighborhoods for so long, officials said, that they collectively have faced arraignment on charges more than 850 times and repeatedly returned to the street, including one who was convicted of stabbing someone to death and later released on parole.
This time, officials said, law enforcement made a concerted effort to build a case that would lead to lengthy prison terms.
In 2011, Boston police and the Federal Bureau of Investigation determined that the gang from Woodward Avenue had formed a lucrative alliance with another gang from Hendry Street in Bowdoin-Geneva, law enforcement officials allege.
As a team, the two gangs operated a sophisticated drug pipeline that stretched to California, Maine, and Miami, flooding Boston’s streets with thousands of Oxycodone pills, kilos of crack cocaine, and hundreds of pounds of high-grade marijuana.
Investigators described a meticulous operation that began when a cooperating witness agreed to work with authorities and buy drugs. From August 2011 through October 2012, the cooperating witness bought crack cocaine, high-grade marijuana, and Oxycodone on Woodward Avenue, Hendry Street, and other places in Boston, according to documents provided by prosecutors. The witness made a total of 30 buys, many of which were recorded on videotape.
The drug buys gave investigators enough evidence for electronic wiretaps on scores of cellphones, providing investigators a rare understanding of the flow of drugs into Massachusetts, according to the documents. They listened as Jonathan DaSilva, the alleged ringleader from Woodward Avenue, pooled his money with his counterpart from Hendry Street, Alexis Hidalgo, combining resources to repeatedly purchase kilos of cocaine, thousands of Oxycodone pills, and hundreds of pounds of marijuana, according to the documents.
Officers listened, according to the documents, as suspects made phone calls for gun deliveries, a task that seemed as effortless as ordering a pizza. Davis said the suspects ordered killings but that police intervened to prevent violence and protect residents.
Over the summer, police parked a patrol car in front of a big yellow house at 37 Hendry St. Davis said the suspects were so nonchalant about the police presence that they simply told buyers to go to the back door.
At the press conference, US Attorney Carmen M. Ortiz stood before three tables piled with evidence: three handguns, a slab of cocaine that looked like a large block of feta cheese, and plastic bags brimming with fragrant marijuana buds.
‘I’m anticipating a much quieter summer because of the work that occurred this winter.’
Ortiz described the raid as “the dismantling of two Boston street gangs whose members have terrorized the community, intimidated witnesses, and brought drugs and guns into our neighborhoods.”
On Woodward Avenue and in Bowdoin-Geneva, the overwhelming majority of residents are law-abiding citizens. Those residents have hungered for lasting peace amid bursts of violence that claim lives and give the neighborhood a bad reputation.
“Anytime police clean up the streets and make it safer for people to walk around is a good thing,’’ said soccer coach Jack Mayhew, whose family has lived in Bowdoin-Geneva for more than 40 years.
The investigation brought charges against 30 people, which included 27 arrested Thursday, two who were already in custody, and one man who remains a fugitive.
Authorities identified him as Jackson Barros, 30, of Dorchester, and encouraged him to surrender.
Nine of the accused defendants, including the two alleged ringleaders, DaSilva, 29, and Hidalgo, 31, appeared before Magistrate Judge Robert B. Collings in a courtroom packed with relatives and friends.
The accused walked into the courtroom one-by-one, wearing leg shackles and handcuffs. An assistant US attorney read off the maximum penalties: Hidalgo, DaSilva, and another defendant, Moises “Mo” Figueroa, 33, all face maximums of life in prison and up to $4 million in fines.
When Collings asked the nine defendants whether they could afford their own lawyer, only Hidalgo answered “yes.”Brian Ballou, Maria Cramer, John R. Ellement and Meghan E. Irons of the Globe staff contributed to this report. Andrew Ryan can be reached at email@example.com. Follow him on Twitter @globeandrewryan