(CNN) — Federal juries indicted four men in connection with the smuggling operation that left 53 immigrants dead after they were trapped in the back of a suffocating truck last month, a tragedy a Homeland Security Investigations agent called the incident. deadliest human smuggling operation in US history.
Jurors returned the indictments in San Antonio on Wednesday. Homero Zamorano Jr., 46, of Pasadena, Texas, and Christian Martinez, 28, of Palestine, Texas, are charged with one count each of conspiracy to transport undocumented immigrants resulting in death; transportation of undocumented immigrants resulting in death; conspiracy to transport undocumented immigrants resulting in serious bodily injury and endangering lives; and the transportation of undocumented immigrants resulting in serious bodily injury and endangering lives, according to a Justice Department news release.
If convicted, the men could face the death penalty on the most serious charges, the Justice Department said.
Authorities were able to connect Zamorano and Martinez to the operation through surveillance footage and phone communications obtained through a search warrant, the Justice Department said.
Juan Claudio D’Luna-Mendez, 23, and Juan Francisco D’Luna-Bilbao, 48, both citizens of Mexico, are also charged with one count each of possessing a firearm while in the US illegally. USA, according to the Department of Justice. If convicted, the agency says they could face up to 10 years in prison.
CNN has reached out to the attorneys for each for comment.
D’Luna-Mendez and D’Luna-Bilbao were initially charged the same day the migrants were found, after agents discovered the truck’s license plate was registered to an address in San Antonio, CNN previously reported.
While surveilling the house, police saw both men in the residence and found a firearm in the console of a truck D’Luna-Bilbao was driving.
Both men are Mexican citizens who were illegally residing in the United States, according to the affidavit.
In addition to the 53 people who died, nearly a dozen others were hospitalized for heat-related conditions after becoming trapped inside a refrigerator trailer truck that was found abandoned outside San Antonio.
Authorities were alerted to the scene on June 27 after an employee working in a nearby building heard cries for help. When they arrived, authorities found the tractor-trailer full of people, some on the ground and in nearby brush, “many of them deceased and some incapacitated,” according to the Justice Department.
Firefighters said patients on scene were hot to the touch and suffering from heat stroke and exhaustion. The truck apparently did not have a working air conditioner and there was no sign of water inside, according to San Antonio Fire Chief Charles Hood.
CNN’s Elizabeth Wolfe, Nicole Chavez, Amir Vera, Joe Sutton, Amy Simonson, Amanda Musa, Travis Caldwell, Priscilla Alvarez, Rosalina Nieves and Raja Razek contributed to this report.