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. Twenty more were transported to hospitals with life-threatening injuries, and another eight had non-life-threatening injuries.

Authorities said someone had contacted the manager at the Walmart, which is 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.

Firefighters were called to the scene at about 12:30 a.m. Sunday and made the discovery. At least 29 fire units and two AirLIFE choppers responded to the scene to take care of the victims.

San Antonio police and the U.S. Immigrant and Customs Enforcement agents also were called to 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 driver of the semi was in custody, McManus said.

Have a news tip? Email, visit our Facebook page or Twitter

► Make it easy to keep up to date with more stories like this. Download the WFMY News 2 App now