Jurors returned the charges to San Antonio on Wednesday, accusing Homero Zamorano Jr., 46, of Pasadena, Texas, and Christian Martinez, 28, of Palestine, Texas, each charged with conspiracy to transport undocumented migrants. which resulted in death; transport of undocumented migrants as a result of death; conspiracy to transport undocumented migrants that causes serious bodily harm and endangers life; and the transportation of undocumented migrants that causes serious bodily injury and endangers life, according to a Justice Department press release.
If convicted, men could face the death penalty on more serious charges, the DOJ said.
Authorities were able to connect Zamorano and Martinez with the operation through surveillance images and telephone communications obtained through a search warrant, the DOJ said.
Juan Claudio D’Luna-Méndez, 23, and Juan Francisco D’Luna-Bilbao, 48, both Mexican citizens, are also charged with possession of a firearm while they were illegally in the United States, according to the DOJ. If convicted, the agency says they could face up to 10 years in prison.
CNN has contacted each man’s lawyers to comment.
D’Luna-Méndez and D’Luna-Bilbao were initially charged the same day the migrants were found, after officers found that the truck’s license plate was registered at a San Antonio address, CNN previously reported.
While guarding the home, police saw the two men at the residence and found a firearm on the console of a truck driving D’Luna-Bilbao.
The two men are Mexicans residing illegally in the United States, according to the affidavit.
In addition to the 53 people who died, nearly a dozen more were hospitalized for heat-related conditions after being trapped inside a refrigerated tractor-trailer that was found abandoned on the outskirts of San Antonio.
Authorities were alerted to the scene on June 27 after an employee working in a nearby building heard screams for help. When they arrived, authorities found the tractor-trailer full of people, some on the ground and in a nearby brush, “many of them dead and some of them incapacitated,” according to the DOJ.
Firefighters said local patients were hot to the touch and suffering from heat stroke and exhaustion. According to San Antonio fire chief Charles Hood, the truck had no apparently functional air conditioning and no water sign inside.
Temperatures on the day the truck was found ranged from 90 degrees to 100 degrees, according to the National Weather Service.
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.