The gun used in the attack against U.S. Immigration and Customs Enforcement Special Agent Jaime Zapata has been traced back to three suspected gun smugglers in Texas.
According to the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), the men were arrested following a raid just outside Dallas in the suburb of Lancaster.
Court records show that authorities first learned about the activities of the two brothers during an undercover investigation back in November 2010.
Two of the men are identified as 27-year-old Ranferi Osorio and his brother 22-year-old Otilio Osorio.
A third suspect, Kelvin Leon Morrison is a neighbor of the two brothers who was allegedly in the car with them when agents confiscated 40 guns during a stop in November 2010.
Otilio Osorio is accused of buying a gun back in October that was later nvolved in the fatal attack on Zapata in San Luis Potosi.
One of the three guns used in his death was a Draco 762 with serial numbers partially removed.
Investigators were able to restore ther serial number and trace the gun back to a store named Off Duty Enterprise in Joshua, Texas.
Federal authorities learned that Otilio Osorio bought the weapon at the store.
During a February 24th raid at their Lancaster home, the Osorio brothers admitted to being involved in the sale of firearms.
The U.S. Attorney's Office for the Northern District of Texas reported that all three men were arrested in Lancaster on Monday.
A detention hearing for Morrison and Otilio Osorio was scheduled before U.S. Magistrate Judge Paul D. Stickney in Dallas at 2 p.m. Tuesday.
Ranferi Osorio TMs detention hearing was scheduled before Judge Stickney at 2 p.m. Friday.
The Associated Press is reporting that the hearing for Morrison and Otilio Osorio was postponed for later this week at defense attorney's request.