SAN ANTONIO – A deadly smuggling operation was discovered in a San Antonio Walmart parking lot early Sunday morning.

Emergency responders found dozens of people in distress inside a hot semi-trailer located at a Walmart in southwest San Antonio. Police said there was a total of 38 victims found in and around the trailer after an employee of the store notified authorities.

Of the 38 victims, eight were pronounced dead at the scene. 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.

Seventeen of the victims had life-threatening injuries and were taken to University Hospital and San Antonio Military Medical Center. Thirteen of the victims had non-life threatening injuries and were taken to five other area hospitals.

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A similar tragedy happened over 15 years ago near Victoria, Texas when 19 undocumented immigrants died after being left in an airless trailer.

In May of 2003, authorities found a tractor-trailer packed with more than 70 immigrants from Mexico, Central America and the Dominican Republic, CBS News reported. Nineteen of the immigrants died from dehydration, overheating and suffocation during the smuggling attempt from South Texas to Houston.

The truck driver, Tyrone Williams, had abandoned the trailer at a truck stop near Victoria, Texas, about 100 miles southwest of Houston. In 2007, Williams was convicted on 58 counts of conspiracy, harboring and transporting immigrants, CBS News reported. He was sentenced to life with no possibility for parole.

Prosecutors said Williams originally earned a death sentence because he intentionally caused the immigrants' deaths by not freeing them when he knew their lives were in danger, CBS News reported.

It was not until 2011 that Williams was resentenced to nearly 34 years after a federal appeals court overturned the multiple life sentences he received, CBS News reported. The 5th U.S. Circuit Court of Appeals ruled Williams was not eligible for capital punishment and the court also said that U.S. District Judge Lee Rosenthal, who presided over the trial, should have sentenced Williams on those counts.

The Victoria case is known as the deadliest human smuggling case in the United States.