The San Antonio Fire Chief has revealed the unimaginable horror inside of a tractor-trailer where 46 men and women were found dead.
"We're not supposed to open up a truck and see stacks of bodies in there," said Fire Chief Charles Hood during a live press conference Monday. "None of us come to work imagining that."
An additional 16 people (12 adults and four children) were rushed to nearby hospitals in varying conditions Monday after multiple police, fire trucks and ambulances responded to the scene at the 9600 block of Quintana Road, authorities confirmed during a press conference.
Two were admitted to University Hospital and at least five were brought to Baptist Medical Center in unknown conditions, PEOPLE confirmed.
Chief Hood said that the victims, who are believed to be undocumented migrants, "were hot to the touch." He added, "They were suffering from heat stroke, heat exhaustion. No signs of water in the vehicle. It was a refrigerated tractor-trailer but there was no visible working AC unit on that rig."
As of 6 a.m. Tuesday, the total number of deceased is 50, and Homeland Security Investigations has detained three individuals believed to be part of the alleged smuggling conspiracy, a U.S. Immigration and Customs Enforcement spokesperson told PEOPLE.
Temperatures in San Antonio reached a high of 103 degrees on Monday.
The 16 taken to the hospital are expected to survive, Chief Hood said, also noting that no children are among the deceased.
It is not clear how many people were in the tractor-trailer when it was abandoned near train tracks and an auto salvage yard. Not everyone has been accounted for.
Chief Hood also said a number of individuals "got out."
Three people are in custody, but it's not clear if they're connected to the incident, Chief William P. McManus said during the press conference.
"This is nothing short of a horrific tragedy," San Antonio mayor Ron Nirenberg added. "Our job is not to ask why. Our job is to ask how we can help. That's why you're seeing medical assistance. As far as the federal investigation goes, that's in the hands of the feds. I'm sure there will be more questions and hopefully some answers as we move forward."
On Monday, a U.S. Immigration and Customs Enforcement (ICE) spokesperson told PEOPLE, "On June 27, Homeland Security Investigations (HSI) responded to a call from San Antonio Police Department (SAPD) in reference to an alleged human smuggling event involving a tractor trailer on Quintana Road near Cassin Road. Upon arrival in the scene, HSI confirmed more than 40 deceased individuals."
Eric Gay/AP/Shutterstock Tractor trailer deaths, San Antonio
They added, "HSI continues its enforcement efforts to ensure the safety and well-being of our communities. We will continue to address the serious public safety threat posed by human smuggling organizations and their reckless disregard for the health and safety of those smuggled. To report suspicious activity, we encourage people to call the HSI Tip Line at 1-866-DHS-2ICE. All calls are kept confidential."
The San Antonio Fire Department confirmed to PEOPLE that this is "an active and ongoing incident" with the investigation being led by Homeland Security Investigations (HSI).
Homeland Security Investigations San Antonio confirmed to PEOPLE the agency is on scene and will lead a federal investigation.
HSI San Antonio has initiated the investigation with support of SAPD. Details will be released as they are available, and the criminal investigation remains ongoing.