SAN DIEGO—A six-month multiagency effort has resulted in 39 arrests and dozens of charges against street gang members allegedly operating in San Diego County at the behest of incarcerated gang members with ties to Mexico’s cartels, the San Diego County district attorney said Jan. 21.

The arrests were made last Thursday, and many suspects are accused of being involved in a variety of crimes, including murders, attempted murders, robberies, arson, extortion, drug and weapons trafficking, and violent assaults.

Prosecutors allege these defendants acted on the orders of the largest prison gang, the Mexican Mafia, also known as La Eme.

“These criminals took orders from cartel bosses operating in state prison and preyed on business owners by forcing mafia-style taxes,” San Diego County District Attorney Summer Stephan said at a press conference.

They also “dealt illegal drugs, including pounds of deadly fentanyl, committed widespread violence, and trafficked weapons such as ghost guns and AR-15s,” she said.

Of 20 different cases, one involves a murder allegedly committed by a 15-year-old suspect, who was provided a weapon by an older gang member.

In another case, an order was allegedly given to attack a business with grenades. “Why? Because the owner refused to pay the tax that was imposed by the Mexican Mafia,” Stephan said. Other businesses were hit with Molotov cocktails or robbed.

Mexican Mafia members gave orders from behind prison walls through cellphones, Stephan said.

A key gang member that gave orders is Ronaldo Mudrano Ayala, 74, of San Diego, Stephan said, who was sentenced to death for murdering three people and attempting to murder a fourth.

“However, our California Department of Corrections decided to close down death row and to release him into a general population where he has even more influence and access to gang members on the streets,” Stephan said.

The six-month undercover investigation was dubbed Operation “Los Impuestos,” which means “taxes” in Spanish. Guns and drugs confiscated during the operation include 21 hand guns, 23 rifles, four shotguns, two grenades, 75 pounds of methamphetamine, 60 pounds of fentanyl, close to two pounds of cocaine, and more than 4,000 M30 fentanyl pills, according to the district attorney’s office.

San Diego law enforcement said that gang activities had been terrorizing communities before the takedown. “It had been an ongoing thing,” San Diego Police Department Lt. Chris Tivanian said at the press conference, but “victims were very reluctant to come forward.”

“There was no ambiguity. They were told that if you call law enforcement, what we’re doing to you now will only get worse,” Tivanian said. Gang members had threatened to vandalize or burn business, and beat or kill employees, he said.

Law enforcement said the arrests will bring peace to the communities for a period of time, but there is still more work to be done.

According the San Diego County district attorney’s office, the Mexican Mafia was initially formed in the California state prison system and has been in existence for more than 50 years. Now it also operates in other states and in the Federal Bureau of Prisons. The prison gang controls and utilizes gang members who are both in custody and out of custody for their criminal enterprises.