United States authorities investigating the suspected human trafficking case said on Monday that 10 victims had died after being found inside a locked, overheated lorry trailer in Texas.
Federal prosecutors vowed to identify and bring to justice the suspected human traffickers responsible for the deaths.
The lorry driver was arrested immediately at the scene.
James Bradley, Jr, 60, a resident of Clearwater, Florida, was in federal custody in connection with the case and is expected to make his first appearance in federal court in San Antonio.
Police in San Antonio were called after midnight on Sunday by store employees to a Walmart parking lot where the lorry conveying 38 people was parked.
The 39th occupant, who had fled into a nearby wooded area, was found a few hours later.
Survivors were hospitalised, including 20 persons in a serious or critical condition.
The ninth person had died late on Sunday.
The nine victims that died were adult males, the Justice Department said.
San Antonio authorities said that children were among the survivors.
Richard Durbin Jr, U.S. Attorney for the Western District of Texas, said the trailer occupants were victims of “ruthless human smugglers.”
“The temperature was at least 37 degrees Celsius late Saturday in San Antonio, 230 km from the Mexican border.
“The temperature inside the trailer would have been much higher,’’ the authorities said.
In three previous incidents this month in San Antonio area, federal agents found 72 people, 33 people and 16 people from Mexico, Ecuador, Guatemala and El Salvador inside locked trailers.