The suspected driver of a truck packed with dozens of migrants who died in blazing heat in Texas was allegedly under the influence of methamphetamine, a US lawmaker has revealed.
Fifty-three migrants lost their lives, making it the deadliest such trafficking incident on record in the US.
San Antonio police officers found Homero Zamorano Jr, a Texas native, hiding in brush near the abandoned truck on Monday, according to documents filed in federal court on Thursday.
US Representative Henry Cuellar, a Democrat whose district includes the eastern part of San Antonio, told Reuters that Mr Zamorano was found to have had methamphetamine, a powerful synthetic drug, in his system.
Mr Cuellar said he was briefed on the matter by US Customs and Border Protection but did not know how authorities made that determination.
A Customs official, speaking on the condition of anonymity, separately told Reuters that Mr Zamorano had methamphetamine in his system.
Mr Zamorano, 45, will appear in a federal court in San Antonio. If convicted, he faces a maximum sentence of life in prison or possibly the death penalty, according to the US Department of Justice.
Officials described finding the trailer’s rear door ajar with bodies stacked inside that were hot to the touch. In nearby brush, officers discovered other victims, some deceased.
They found Mr Zamorano hiding near the victims and escorted him to a local hospital for medical evaluation, prosecutors said. Mexican officials said he had tried to pass himself off as one of the survivors.
The truck had been carrying migrants from Mexico, Guatemala, Honduras and El Salvador and was found in a desolate, industrial area near a highway on the outskirts of San Antonio, Texas, about 260 kilometres north of the US-Mexico border.
Temperatures in the area that day had soared as high as 39.4 degrees, and authorities called to the scene found no water supplies or signs of working air-conditioning inside the cargo trailer.
Mexicans accounted for about half of those who perished. Eleven people – including minors – remain hospitalised. In addition to 27 Mexicans, the victims included 14 Hondurans, seven Guatemalans and two Salvadorans, Mexico’s government said.
The nationalities of another 17 of the migrants in the truck remained unclear, prosecutors said. Most of the victims were male, with 13 women and girls among the dead, the Bexar County medical examiner’s office said.
Officials believe the migrants boarded the truck on the US side of the border with Mexico.
Mr Cuellar said the migrants had likely crossed the border and gone to a “stash house” before being picked up by the trailer and passing a checkpoint.
They likely then went into San Antonio and, where the truck experienced mechanical issues that left them in the back without air-conditioning or ventilation, Mr Cuellar said.
Prosecutors also accused Christian Martinez, 28, of conspiring with Mr Zamorano and charged him with a human trafficking offence. He made an initial appearance in a court in the Eastern District of Texas on Wednesday.
Two other men suspected of involvement in the incident, both Mexican nationals, were charged on Tuesday in US federal court with possessing firearms while residing in the country illegally.