A gun used in the fatal shooting of a US immigration agent in Mexico was bought in Texas, where three men were arrested Monday in connection with a smuggling operation, authorities told AFP.
The arrests were made during raids on two homes in the Dallas suburb of Lancaster, according to a spokesman for the US Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).
"It was documented that these guys were trafficking weapons," ATF spokesman Thomas Crowley told AFP in a telephone interview.
Crowley said he could not immediately release the identities of the men, nor specify the charges against them. All three are US citizens and Texas residents in their mid-to-late 20s, and two are brothers, he said.
Investigators traced one of the three guns they recovered from the February 15 fatal shooting of US Immigration and Customs Enforcement agent Jaime Zapata to Texas, which led to the raids Monday, Crowley said.
"It was used in the shooting," he said. "We don't know if it was the one that killed agent Zapata, but it was definitely used in the shooting."
The 7.62 millimeter-caliber pistol in question was bought in Texas about six months ago, and later was smuggled into Mexico, Crowley said.
The US Department of Justice was expected to release more information later Monday, he said.
Zapata, 32, and a second ICE agent came under fire while driving in the Mexican state of San Luis Potosi in a region plagued by drug violence. Zapata died from his wounds.
Mexico's military on Sunday arrested an alleged leader of the Zetas drug gang who was reported to be the boss of the shooter, Julian Zapata Espinosa, in the deadly attack.
Julian Zapata Espinosa allegedly confessed to the attack but said that the US agents' armored car had been confused with one belonging to a rival gang, Mexican media reported.