Authorities have charged two more people in connection with a human smuggling tragedy that left 53 people dead, bringing the total number of suspects charged to four.

Texas resident Homero Zamorano Jr., 45, has been charged with one count of alien smuggling resulting in death, according to a Wednesday announcement from the U.S. Attorney’s Office for the Western District of Texas.

If convicted, authorities say that Zamorano faces up to life in prison or the death penalty.

Charges were issued against Zamorano after he was identified as the suspected driver of a truck found abandoned in southwestern San Antonio on June 27. When authorities arrived on the scene, they found dozens of people dead from heat-related illness, some in the trailer and some in the surrounding area.

San Antonio Police Department (SAPD) officers were led to Zamorano “who was observed hiding in the brush after attempting to abscond.” He was placed into custody by SAPD.

According to reports, Zamorano presented himself as one of the surviving migrants after he was found in the brush. Reports also quote local law enforcement claiming that Zamorano was possibly on methamphetamine at the time of his arrest.

Authorities noted that “Laredo Sector Border Patrol provided Homeland Security Investigations (HSI) agents surveillance footage of the tractor trailer crossing through an immigration checkpoint. The driver could be seen wearing a black shirt with stripes and a hat. HSI agents confirmed Zamorano matched the individual from the surveillance footage and was wearing the same clothing.”

Juan Claudio D’Luna-Mendez, 23, and Juan Francisco D’Luna-Bilbao, 48, both citizens of Mexico, have been charged with possession of a weapon by an alien illegally in the U.S. in connection with the human smuggling incident.

The U.S. Attorney’s Office also announced charges against a fourth person on Wednesday. Christian Martinez, 28, was arrested on June 28 in Palestine and has been charged with conspiracy to transport illegal aliens resulting in death.

According to court documents, “a search warrant was executed on a cell phone belonging to Zamorano. Through investigation, it was discovered that communications occurred between Zamorano and Martinez concerning the smuggling event. If convicted, Martinez faces up to life in prison or could face the death penalty.”