Forty-six men and women have been found dead in an 18-wheeler in southwest San Antonio, Texas. They are all believed to undocumented migrants.
The San Antonio Police Department shared details of the "horrific tragedy" on Monday.
Chief William P. McManus said in a live press conference via Facebook that police received the first call at 5:50 p.m. local time. An employee who worked at a nearby building "heard a cry for help" and "came out to investigate." Upon approaching the truck, he saw the door was "partially open" and soon found the 46 dead individuals inside.
An additional 16 people (12 adults and four children) were rushed to nearby hospitals in varying conditions after multiple police, fire trucks and ambulances responded to the scene at the 9600 block of Quintana Road.
Two were admitted to University Hospital and at least five were brought to Baptist Medical Center in unknown conditions, PEOPLE confirms.
Chief McManus added that three people are now in custody; however, it's not clear if they're "absolutely connected" to the deaths.
San Antonio Fire Chief Charles Hood said the fire department was called to the scene over reports of a dead individual. Upon arrival, they found the trailer with one body outside and multiple bodies inside.
"The patients that we saw were hot to the touch," Chief Hood said of the victims. "They were suffering from exhaustion, no signs of water in the vehicle." There was also no working air conditioning unit on the vehicle.
"We're not supposed to open up a truck and see stacks of bodies in there," he continued. "None of us come to work imagining that."
Those taken to the hospital were conscious "at the time of transportation," he added, later saying that they're expected "to survive."
The trailer was crammed full of people as temperatures in San Antonio reached a high of 103 degrees.
It is not clear how many people were in the tractor-trailer when it was abandoned near train tracks and an auto salvage yard, or how long they had been inside. Not everyone has been accounted for.
"This is nothing short of a horrific tragedy," said San Antonio mayor Ron Nirenberg. "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."
Eric Gay/AP/Shutterstock Tractor trailer deaths, San Antonio
A U.S. Immigration and Customs Enforcement (ICE) spokesperson tells 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."
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."
San Antonio Fire Department confirms 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 confirms to PEOPLE the agency is on scene. The agency will lead a federal investigation.
HSI San Antonio has initiated an investigation with support of SAPD. Details will be released as they are available, and the criminal investigation remains ongoing.
San Antonio is expecting an estimated 19,000 migrants to pass through the city this June as the federal government will provide $10.8 million in reimbursements through the Emergency Food and Shelter Program for hotel rooms, food and a planned processing center, according to KSAT-TV.
"We've seen unprecedented numbers coming through San Antonio" Assistant City Manager Lori Houston told the outlet. "The past three months, we've seen about 50,000 migrants coming to San Antonio from the border."
Monday's tragedy is one of the deadliest in recent history involving migrants. In 2019, a similar fatal road crossing incident in England resulted in the deaths of 39 Vietnamese migrants, according to Sky News. The victims were found in a similar truck, dying from suffocation and hypothermia.