SAN ANTONIO, TEXAS (WTXF/AP) - Several other people have been taken to hospitals. The driver of the truck was arrested, according to officials.
San Antonio police say a Walmart employee was approached in a parking lot by a person from the truck who was asking for water late Saturday night or early Sunday morning. Police say the employee gave the person the water and then called them and when they arrived they found the eight people dead in the back of the trailer.
Police say they checked surveillance video, which shows vehicles had arrived and picked up other people from the tractor-trailer. They say they're "looking at a human trafficking crime."
Police say the U.S. Department of Homeland Security is involved in the investigation into what happened.
After daybreak Sunday, the truck remained at the side and toward the back of the store. The scene is marked off with yellow crime-scene tape and with officers and patrol cars. The trailer of the 18-wheeler truck has an Iowa license plate. Neither it nor the truck's cab appear to have markings.