Eight people were found dead Sunday morning inside an 18-wheeler in the parking lot of a Walmart store in San Antonio, city police and fire officials said.
A total of 38 people had been inside the tractor-trailer, including two school-age children, authorities said. Twenty people were taken to area hospitals in critical condition, and another eight had less critical injuries.
The vehicle did not have a working air conditioning system, authorities said.
Authorities were first alerted by a store employee who called the police after being approached by someone from the truck who was asking for water.
Late last night we got a call from a Walmart employee about a welfare check in a tractor-trailer that was parked in the lot here, Police Chief William McManus said.
According to police, surveillance video from the store showed "a number of vehicles" picking up people who survived the trip that were inside the trailer.
Some people fled into the woods, and police will conduct another search in the morning, the chief said.
The driver of the vehicle, who was not identified, has been taken into custody, authorities said.
Were looking at human trafficking crime here this evening, McManus said. The U.S. Department of Homeland Security is also looking into the incident.
The origin of the truck is still unknown.
U.S. Immigration and Customs Enforcement personnel will investigate after those needing medical attention have been treated, authorities said.