The driver of a sweltering tractor-trailer found packed with immigrants outside a Walmart in San Antonio has been charged over the deaths of 10 of his passengers and could face the death penalty over the hellish journey.
In outlining their immigrant-smuggling case against James Matthew Bradley Jr, federal prosecutors depicted the trailer as pitch-black, crammed with around 90 people or more by some estimates, and so suffocatingly hot that one passenger said they took turns breathing through a hole and pounding on the walls to get the driver’s attention.
Bradley, from Clearwater, Florida, appeared in federal court on charges of illegally transporting immigrants for financial gain, resulting in death.
The 60-year-old did not enter a plea or say anything in court about what happened.
Bradley was assigned a public defender and ordered held for another hearing on Thursday.
Over the weekend, authorities discovered eight bodies inside the crowded 18-wheeler parked in the summer heat, and two more victims died in hospital.
Officials feared the death toll could rise because nearly 20 others rescued from the rig were in dire condition, many suffering from extreme dehydration and heatstroke.
Bradley told investigators that the trailer had been sold and he was transporting it for his boss from Iowa to Brownsville, Texas.
He said he did not realise people were inside until he parked and got out to relieve himself.
After hearing banging and shaking, he opened the door and was "surprised when he was run over by ’Spanish’ people and knocked to the ground", according to the complaint.
Bradley was quoted as telling investigators that he knew the trailer refrigeration system did not work and that the four ventilation holes were probably clogged.
He also said he did not call emergency services, even though he knew at least one passenger was dead.
The truck was registered to Pyle Transportation of Schaller, Iowa.
President Brian Pyle said that he had sold the truck to a man in Mexico and that Bradley was an independent contractor who was supposed to deliver it to a pick-up point in Brownsville.
"I’m absolutely sorry it happened. I really am. It’s shocking. I’m sorry my name was on it," Mr Pyle said, referring to the truck.
He said he had no idea why Bradley took the looping route he described to investigators.
Bradley told authorities that he had stopped in Laredo, Texas - which would have been out of his way if he were travelling directly to Brownsville - to get the truck washed and detailed before heading back 240 kilometres (150 miles) north to San Antonio.
From there, he would have had to drive 275 miles south again to get to Brownsville.
"I just can’t believe it. I’m stunned, shocked. He is too good a person to do anything like this," said Bradley’s fiancee, Darnisha Rose, of Louisville, Kentucky.
"He helps people, he doesn’t hurt people."
She said Bradley told her he had no idea how the immigrants got into his trailer.
One of the passengers told investigators that he was in a group of 24 people who had been in a "stash house" in Laredo for 11 days before being taken to the tractor-trailer.
A passenger told investigators that he and others crossed into the US by raft, paying smugglers 12,500 Mexican pesos (£540).
They were then put aboard the truck to be taken to San Antonio, according to the criminal complaint.
The man said he was supposed to pay the smugglers 5,500 dollars (£4,200) once he got there.
He said that those in the truck were given no water or food and that the immigrants soon began to struggle to breathe and started passing out.
At least some of those in the truck were from Mexico and Guatemala, according to diplomats from the two countries.
Latin Americans who enter the United States illegally often rely on smuggling networks to guide them across the border by foot or raft, put them in safe houses and then give them rides to their destination in the US.
"Even though they have the driver in custody, I can guarantee you there’s going to be many more people we’re looking for to prosecute," said Thomas Homan, acting director of US Immigration and Customs Enforcement.
The tragedy came to light after a person from the truck approached a Walmart employee and asked for water late on Saturday night or early on Sunday morning after a day in which the temperature had climbed over 100F (37.7C), police said.
The employee gave the person water and then called police.
In one of the worst smuggling-by-truck tragedies on record in the US, 19 immigrants locked inside a stifling rig died in Victoria, Texas, in 2003. The driver was sentenced to nearly 34 years in prison.
Activists blamed federal and Texas authorities’ hard-line immigration policies for contributing to the latest deaths by forcing immigrants to take greater risks to reach the US.
"These tragedies are compounded when it’s incredibly dangerous and incredibly expensive and we push migration into the hands of illicit actors," immigration activist Bob Libal said.