In another example of the increasing U.S. response to Mexico’s demands that it do more to stop the flow of weapons to the cartels, a two-year investigation by a U.S. government task force has broken up an arms-trafficking ring responsible for military-grade firearms being sent across the border.

The investigation by the multi-agency body called the Homeland Security Task Force resulted in 100 weapons and 125,000 rounds of ammunition being seized and 28 indictments secured.

Among the detained is Fernando Daniel Castro, a 24-year-old from Phoenix identified as the ringleader. He is accused of creating a multi-level operation in which he and other defendants would purchase weapons legally and then sell them at a profit to others who, with Castro’s knowledge, would smuggle them into Mexico.

All of those actions are against the law, even the original purchase of the weapons from licensed dealers, since Castro allegedly made “false statements during the purchase of a firearm.”

“Every single illegal firearm and round taken off the street today represents potential lives saved,” Jason Stevens, the special agent in charge for Homeland Security Investigations in Arizona, said on Tuesday.

The Mexican government has long called on the U.S. to do more to stop the flow of firearms to Mexico, where U.S.-sourced weapons are often used by criminal organizations to commit crimes. An estimated 135,000 firearms were trafficked from the U.S. to Mexico in 2022.

U.S. Ambassador to Mexico Ronald Johnson praised the task force’s work and other recent weapons busts, promising “we haven’t finished yet.”

Writing on his X account, Johnson said, “Working alongside Mexican authorities, we are holding arms traffickers accountable and making our two nations safer.”

The investigation that led to the indictment of Castro grew out of previous operations involving other defendants.

Earlier this year, Emmanuel Rabena-Velderrain, from Mexico, pleaded guilty after being caught trying to cross the border into Mexico on Feb. 17, 2025, with 42 AK-style rifles and 42 7.62×39 magazines in his vehicle. 

On April 27, 2026, U.S. District Judge Susan M. Brnovich sentenced Amairany Guadalupe Armendariz Álvarez, from Mexico, to 24 months in prison for being an “alien in possession of a firearm.” Álvarez admitted in her plea to entering the United States to pick up three M249 rifles and a Colt pistol.

With reports from ABC15