If convicted, the men could face the death penalty on the most serious charges, the DOJ said. Authorities were able to link Zamorano and Martinez to the operation through surveillance video and phone communications obtained through a search warrant, the DOJ said. Juan Claudio D’Luna-Mendez, 23, and Juan Francisco D’Luna-Bilbao, 48, both citizens of Mexico, are also charged with one count of possession of a firearm while in the U.S. illegally, according to the DOJ . If convicted, the agency says they could face up to 10 years in prison. CNN reached out to attorneys for each man for comment. D’Luna-Mendez and D’Luna-Bilbao were initially charged the same day the migrants were found after officers determined the license plate on the truck was registered to an address in San Antonio, CNN previously reported. During surveillance at the home, police saw both men at the residence and found a firearm in the console of a pickup truck driven by D’Luna-Bilbao. Both men are Mexican nationals who were in the U.S. illegally, according to the affidavit. In addition to the 53 people who died, nearly a dozen others were hospitalized for heat-related conditions after becoming stuck inside a refrigerated tractor-trailer that was found abandoned on the outskirts of San Antonio. Authorities were called 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 dead and some disabled,” according to the Justice Department. Fire officials said patients at the scene were warm to the touch and suffering from heatstroke and exhaustion. The truck apparently had no working air conditioning and there was no sign of water inside, according to San Antonio Fire Chief Charles Hood. Temperatures the day the truck was found ranged from the high 90s to the low 100s, 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.