At least nine men have been found dead inside a sweltering tractor trailer parked at a Walmart store in San Antonio, Texas, in what authorities have called a case of "ruthless" human trafficking.
San Antonio Fire Chief Charles Hood said, thirty people, many in critical condition and suffering from heat stoke and exhaustion, were removed from the trailer, which lacked air conditioning or a water supply.
Temperatures outside the vehicle topped 37.8 Celsius.
Authorities initially said eight bodies were found in the trailer, but the US Attorney's Office statement later said the death toll had risen to nine.
San Antonio‑based US Attorney Richard Durbin Jr said all were victims of ruthless human smugglers indifferent to the well‑being of their fragile cargo.
He said these people were helpless in the hands of their transporters.
The truck's driver, identified as James Mathew Bradley of Florida, was arrested in connection with incident.
A criminal complaint will be filed in federal court in San Antonio and Bradley is expected to have an initial court appearance shortly afterwards.
The bodies of the deceased, who have not yet been identified by authorities, were discovered after officials were led to the trailer by a man who had approached a Walmart employee and asked for water.
San Antonio is about 240 km north of the border with Mexico.
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