Police are investigating a suspected human trafficking ring after eight immigrants, including two children, were found dead inside a truck in a Walmart car park.
They are suspected to have died from heatstroke or dehydration after being locked in the lorry without air conditioning or water.
At least 30 more people have been taken to hospital, with at least 20 believed to be in a life threatening condition.
The lorry was found parked in a Walmart car park in San Antonio, Texas, after a manager suspecting it contained illegal immigrants contacted cops.
Speaking at the scene, Police chief William McManus said the driver of the video was in custody, KENS5 reported.
He said: “Late last night we had a call from a Walmart employee, to conduct a welfare check on a truck and trailer that was parked in the lot here.
“He was approached by someone from that truck who was asking for water, he came back with water, he called the police.
“We arrived on the scene and found eight people dead in the back of that trailer.
“There were a number of people who were transported to local hospitals, checking the video from the store we found that there were a number of vehicles that came in and picked up a lot of the folks from inside that trailer who survived that trip.”
Charles Hood, the San Antonio Fire Chief, told reporters the air conditioning was not working inside the lorry.
“Each one of them had heart rates of over 130 beats per minute.
“These people were inside this trailer without any signs of any water, so you’re looking at a lot of heatstroke, a lot of dehydration.
“We’re very fortunate that there wasn’t 38 of these people that were all locked inside the vehicle dead.”