More than 40 migrants were found dead Monday in the trailer of a big-rig truck in San Antonio, authorities said.
San Antonio Fire Chief Charles Hood said that at least 46 people were dead and that 16, including four children, had been hospitalized.
The victims included both males and females and females, many young adults, officials said.
Three people have taken into custody, San Antonio Police Chief William P. McManus said.
The grim discovery was made early Monday evening in an undeveloped area of southwest San Antonio near the railroad tracks. Someone who works in the area reported hearing a cry for help and spotted at least one body, officials said.
“We’re not supposed to open up a truck and see stacks of bodies in there,” the fire chief said.
The police chief said the survivors lacked water and air conditioning. “The patients that we saw were hot to the touch,” he said.
McManus said Homeland Security Investigations has taken over the investigation. The heat will likely be a focus for those investigating the deaths. Temperatures climbed to 101 on Monday, according to the National Weather Service.
The heat inside a trailer packed with humans was likely significantly greater than the high temperature might indicate.
A committee of the National Association of Medical Examiners has recommended that bodies with a temperature of 105 or greater at the time of collapse be certified as heat-related deaths.
In 2017, 10 migrants died in a packed truck carrying 39 people in San Antonio in the heat of summer.
Driver James Mathew Bradley Jr., 60, of Clearwater, Fla., pleaded guilty to conspiracy and transporting migrants, although his wife said he did not know people were in the trailer.
— This is a developing story; check back for updates.