More than 400 law enforcement officers carried out a flurry of predawn raids in the Boston area Thursday morning, rousing suspected gang members from their sleep in the culmination of a 14-month investigation into drugs and firearms trafficking.
Federal and state prosecutors announced charges against 66 people in the far-reaching probe, which targeted members of four street gangs whose operations stretched from Lynn to Brockton.
“I believe we have taken out the leadership,” US Attorney Carmen Ortiz said, flanked by federal and state law enforcement officers at a news conference at the J. Joseph Moakley Courthouse in South Boston.
The gangs, which have a heavy presence in East Boston, Brockton, Chelsea, and Everett, were identified as the 18th Street Gang, the East Side Money Gang, the Boylston Gang, and the Orient Heights Gang.
More than 70 firearms, including assault rifles, pistols, and sawed-off shotguns, were seized during the investigation, along with significant amounts of cocaine, crack, and heroin and about $100,000 in cash, Ortiz said.
“A dangerous pipeline of drugs and guns was disrupted and dismantled,” Ortiz said, crediting the cooperation of several law enforcement agencies.
Boston Mayor Martin J. Walsh and Police Commissioner William Evans said the arrests will help reduce gang and drug violence.
“Many of these guns you see in front of us would have taken young people’s lives,” Walsh said, motioning toward nearly 40 firearms confiscated in the raids.
Evans said the scope of the arrests sent a clear message he hoped would serve as a deterrent.
“If you are going to be involved in gangs, then we are going to be on you,” he said. “We are going to find out who you are, and we are going to take you down, like we did today.”
At the same time, officials emphasized that law enforcement efforts cannot reduce gang violence on their own and asked for help from residents in gang-plagued areas.
“We cannot make them safe on our own,” Ortiz said. “We cannot solve crimes on our own. We need them to care, to help us reduce the violence, and to make the community safe.’’
The investigation originally targeted the 18th Street Gang, a multinational outfit, but was expanded to include three other gangs associated with them, said Daniel Kumor, special agent in charge of the Boston office of the federal Bureau of Alcohol, Tobacco, Firearms, and Explosives.
“One of our top priorities is preventing firearms trafficking,” Kumor said. “We have been working to identify how these firearms were illegally trafficked, how they went from legal commerce to illegal commerce, and ultimately ending up in the hands of criminals and trigger pullers.”
Affidavits released Thursday by prosecutors describe brazen acts of violent crime allegedly carried out by the gang members. Investigators relied on a range of methods, from witness interviews to social media, to build the case, Ortiz said.
For instance, Jassel Castillo, 21, of Boston, an alleged member of the Boylston Gang whose street name was “Shells,” boasted about his involvement in a nonfatal shooting last March in Roslindale, investigators said.
Five days after the shooting, he was recorded as saying, “That hit, I just missed, bro,” according to a federal affidavit. “I swear to God when that [target] seen me, he seen death.”
Investigators also targeted Oscar Oliva, who authorities say sold firearms to undercover officers as they recorded the transactions. In photographs filed in court, Oliva is allegedly shown pulling a gun from under his shirt and handing it to the buyer. Another image, from April 2015, allegedly shows Oliva counting cash as he is being paid for illegally selling a gun.
Of the 66 people charged, 43 were arrested Thursday in Boston, Brockton, Chelsea, Everett, Lynn, Revere, and Quincy, prosecutors said. Three were already in custody.
The remaining individuals who were charged are now considered federal or state fugitives, authorities said.
The raids were carried out swiftly, under the cover of darkness, and without incident, Ortiz said. Jonathan Peña, 22, was arrested at his family’s apartment in a public housing complex in East Boston.
His mother, Juana Peña, 51, said she was shocked when about five officers entered her apartment around 5 a.m., using keys to open the doors.
“I was asleep,” she said in Spanish. “I was startled awake when police grabbed me, put my arms behind my back, and then they put [cable ties] on my hands.”
On Thursday, family and friends came to comfort Peña, who was visibly shaken. She had pain in her left arm and neck that she attributed to police force. The officers were at the complex for about four hours, Peña said.
Peña said she had no idea whether her son was involved with a gang and wants to get more information from police.
Rosa Tejada, who identified herself as Jonathan Peña’s aunt, said she was shocked by her nephew’s arrest.
“It’s very calm around here,” Tejada said. “There’s more crime [elsewhere], but here is very calm.”
John R. Ellement of the Globe staff contributed to this report. Kathy McCabe can be reached at Katherine.McCabe @globe.com. Follow her on Twitter @GlobeKMcCabe.