SAN ANTONIO -- An apparent smuggling operation involving undocumented immigrants came to a tragic conclusion early Sunday morning when emergency responders found dozens of people in distress inside a hot semi-trailer at a Walmart in southwest San Antonio.

The San Antonio Fire Department reported that eight people died at the scene. Seventeen more were transported to hospitals with life-threatening injuries, and another 13 had non-life-threatening injuries.

Authorities said an employee at the Walmart encountered a person who was disoriented and asking for water at the store located at I-35 and Highway 16 on the city's southwest side. The person said that there were people inside the trailer outside who needed help.

When police arrived on the scene around 12:30 a.m. Sunday. They detained the driver immediately and searched the trailer to find several people in various stages of medical distress. Firefighters were called to the scene and at least 29 fire units and two AirLIFE choppers responded to the scene to take care of the victims.

Police said there was a total of 38 victims in and around the trailer. Seventeen victims were taken to University Hospital and San Antonio Military Medical Center with life-threatening injuries. The 13 victims with non-life threatening injuries were taken to five other area hospitals.

Eight victims were pronounced dead at the scene and officials said all of the deceased are believed to have died as a result of heat exposure/asphyxiation. Their bodies were taken to the Bexar County Medical Examiner's Office for examination where a cause of death will be determined.

Police do not have positive age ranged and demographics for the injured or deceased. The two youngest victims known are 15-years-old and they are among the injured found.

San Antonio police and the U.S. Immigrant and Customs Enforcement agents also were called to the scene.

Facebook Live from the scene

SAPD Chief William McManus said the trailer appeared to be a smuggling operation. He said the people in the trailer would be reviewed by ICE agents to determine their immigration status.

The San Antonio Fire Department released the following statement:

"Shortly after 12:30AM (Central) the San Antonio Fire Department responded to 8358 IH-35 S. for a report of multiple people in the trailer portion of an 18 wheeler. First arriving units found a number of people in the back of this trailer all in varying degrees of medical distress. A total of 8 individuals were deceased upon our arrival. 17 patients were transported priority 1 (life threatening injury / illness) and 13 were transported priority 2 (not immediately life threatening). Air ambulances (AirLife), and the SAFD Ambus (mobile mass casualty transportation vehicle) were also both utilized to transport the multitude of patients we encountered. A search of the surrounding area was also conducted to attempt to locate any patients that may have attempted to flee the scene. An additional search will be conducted later this morning once the sun has risen. All questions relating to the potential criminal aspect of this should be directed to the San Antonio Police Department."

At early light, the police helicopter returned to search the undeveloped land near the shopping center in an attempt to locate any additional victims.

Richard L. Durbin, Jr. United States Attorney, Western District of Texas released the following statement:

"San Antonio firefighters and police responded to a horrific scene this morning on the southwest side of town. They discovered an alien smuggling venture gone horribly wrong. Eight immigrants were found dead. At least twenty more were in serious condition. All were victims of ruthless human smugglers indifferent to the well-being of their fragile cargo.

The South Texas heat is punishing this time of year. These people were helpless in the hands of their transporters. Imagine their suffering, trapped in a stifling trailer in 100-plus degree heat. The driver is in custody and will be charged. We will work with the Homeland Security Investigations and the local responders to identify those who were responsible for this tragedy."

SAPD Homicide and Homeland Security are jointly conducting the criminal investigation. The driver faces both state and federal charges, police said.