4 indicted in connection to tractor-trailer smuggling operation that left 53 dead in San Antonio

Four men have been indicted in connection to the deadliest known migrant smuggling attempt in U.S. history, where 53 people were found dead inside an abandoned tractor-trailer in San Antonio, Texas.

A federal grand jury in San Antonio returned an indictment against Homero Zamorano Jr., 46, and Christian Martinez, 28, the United States Attorney's Office of the Western District of Texas announced Wednesday.

Both men were charged with one count each of conspiracy to transport and transportation of illegal aliens resulting in death, and conspiracy to transport and transportation of aliens resulting in serious bodily injury and placing lives in jeopardy.

50 adults and three children died during the June 27 smuggling attempt, and 10 adults and one child were injured, officials said. The victims were from Mexico, Guatemala, and Honduras, according to U.S. Immigration and Customs Enforcement.

Many of them suffered from heat stroke and heat exhaustion, San Antonio Fire Department Chief Charles Hood said, and there were no signs of water or working air conditioning unit on the truck.

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Zamorano, of Pasadena, Texas, drove the tractor-trailer across the U.S.-Mexico border, the United States Attorney’s Office said. San Antonio police officers arrested him after he tried hiding in a bush when the truck was discovered in Texas.

Investigators discovered Martinez, from Palestine, Texas, had been communicating with Zamorano about the smuggling after running a search warrant on Zamorano's cell phone.

Both men could face life in prison or the death penalty if convicted.

Also indicted Wednesday were Juan Claudio D’Luna-Mendez, 23, and Juan Francisco D’Luna-Bilbao, 48, who are both Mexican citizens. They were each charged with one count of possession of a firearm while unlawfully present in the United States.

According to the United States Attorney’s Office, investigators located D'Luna-Mendez and D'Luna-Bilbao by tracing the addresses on the tractor-trailer's registration. Authorities found a handgun in the truck D'Luna-Bilbao was driving and additional firearms in the residence.

Both men admitted to possessing illegal firearms and to overstaying their visas, according to the court records. They each face up to 10 years in prison if convicted.

This article originally appeared on USA TODAY: San Antonio migrant smuggling: 4 indicted to the deadly incident