The driver is in custody and many of the injured are in critical condition, suffering from heat stroke and dehydration.
Antonio. A tractor-trailer loaded with immigrants, in the sweltering heat. Police finding 38 people packed inside. Nine have died. The grisly discovery in a Walmart parking lot. 30 people rushed to the hospital. The horror revealed after someone from inside the truck approached a worker, asking for water. That worker calling for police. Now investigators saying there may have been as many as 100 people in the truck. And tonight, the driver is in custody. Here’s Kenneth Moton. Reporter: Tonight, a horrific and deadly case of human smuggling in San Antonio. Federal investigators say 38 immigrants inside this tractor trailer suffocating in excruciating heat. Folks were literally baking in the heat, and did not have access to water. Reporter: Just after midnight, officials making the discovery. The trailer in a Walmart parking lot with no air conditioning. Eight dead, 30 more rushed to the hospital. 20 in critical condition. Suffering from traumatic brain injuries from heat stroke and dehydration. Most of them adults in their 20s and 30s but at least two are young children. Tonight, one more dying at the hospital, bringing the death toll to at least nine. The u.s./mexico border just 50 miles away. The victims could have been in that truck for hours. Temperatures inside, as hot as 140 degrees. Police say video shows survivors jumped out of the truck before being discovered. An employee called 911 when he spotted a man who was desperate for water. Prosecutors say the driver, James Matthew Bradley, has been taken into custody. It was a mass casualty situation. We treat it just like an airline crash. Or any kind of incidents. Kenneth, joining us live from one of the hospitals treating the victims. Authorities saying there may have been up to 100 people crammed into the truck? Reporter: Yes, as many as 100 people were in the back of the truck. Right now, agents are looking for the survivors who ran. Some jumped into waiting cars. All of this as undocumented immigrants fight for their life in the hospital.
This transcript has been automatically generated and may not be 100% accurate.
