It is now dark and only a few law enforcement vehicles and police tape cordoning off a dark road make it clear that this is the scene of a mass casualty event.
The victims, who were supposed to be migrants, probably died from heat exhaustion or dehydration.
Edward Reyna, a security guard at a wooden park a few feet away, says he is not surprised to arrive at his night shift and hear this news.
He has lost count of the times he has seen migrants jump off the train that passes right next to where the truck was found.
“I thought that sooner or later someone would get hurt,” Reyna says. “The cartels that carry them don’t care.”
This story has been played before in Sant Antoni, but not with this magnitude.
In 2017, 10 immigrants were found dead in a similar trailer outside a Walmart, also on the south side of the city.
The southern end of San Antonio is a corridor with two main roads connecting the city with the border towns of Texas.
Most rural communities, the few scrap depots and the handful of developing neighborhoods in this part of the city make it easy for a truck of this size to go unnoticed, until it does.