Three people suspected of smuggling guns to Mexico were arrested in Lancaster on Monday after federal investigators traced the gun used in the killing of a U.S. agent in Mexico to one of them, officials said.
Agents of the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives arrested the suspected gun smugglers in morning, ATF spokesman Tom Crowley said.
Crowley referred questions on other details to the U.S. Justice Department in Washington. A department spokeswoman said no statement was planned for Monday.
The ATF said the gun was used in a Feb. 15 shooting of two federal agents who were driving on a highway near the northern city of San Luis Potosi on Feb. 15. U.S. Immigration and Customs Enforcement agent Jaime Zapata was killed and agent Victor Avila was wounded.
Zapata and Avila, who worked at the U.S. Embassy in Mexico City, were attacked as they returned to Mexico City from a meeting with other U.S. personnel in the state of San Luis Potosi. Avila was shot twice in the leg and is recovering in the United States.
Some reports at the time said the two were stopped at a roadblock, while others said they were run off the road by other vehicles. The Mexican government does not authorize U.S. law enforcement personnel to carry weapons.
Neighbors of the three men who were arrested in Lancaster said they were shocked to hear that ATF agents stormed the two homes early Monday morning.
"I would never have guessed it would be in this neighborhood, right down the street from where i live," said Casey Savins, who lives just a few doors down from where agents arrested the three men.
"When I saw the FBI and the ATF, that's when i start freaking out, thinking this is really serious," Connie Burden said.
Also Monday, the Mexican navy announced that marines had captured a regional boss for the Zetas drug gang that is accused in Zapata's slaying.
Much of northeastern Mexico has seen an increase in bloodshed as the Zetas battle their former allies in the Gulf cartel for control of drug trafficking and other criminal activity. Mexican authorities say Zapata Espinoza told them the two agents were attacked because they were mistaken for members of the rival cartel.
Last week, some U.S. officials said the attack was an intentional ambush of the agents and that the gunmen made comments before they fired indicating they knew who their targets were.
The agents were in a Chevrolet Suburban. Mexico's drug cartels frequently set up roadblocks and ambushes to steal large SUVs and pickups, vehicles they like to use.
NBC DFW's Grant Stinchfield contributed to this report.