Uvalde police said in a statement Friday event that a group of people were found "suffocating" in a train car near Knippa, just east of Uvalde, Texas.
On Saturday, the Department of Homeland Security (DHS) specified that 17 people — 15 men and two women — were found. Two of the men were pronounced dead at the scene.
The Uvalde police statement characterized the people as "undocumented immigrants."
The statement, posted on the police department's Facebook page, explained that at around 3:50 p.m. local time, a 911 call was made to Uvalde Telecommunications Center "from an unknown third-party caller" who told authorities about the people in the train car.
Border Patrol agents were notified, and they stopped the train about three miles east of Knippa.
Uvalde police closed a segment of U.S. Highway 90, between Knippa and Sabinal, so medical helicopters could land and treat the injured.
On Saturday, DHS explained that four people were taken to area hospitals. Their conditions were not immediately known.
In an interview with TPR, Don McLaughlin, the mayor of Uvalde, reported similar information. He said he learned the train had sat on the tracks, in the afternoon sun, for about three hours.
He said, "911 got a call — don't know if it was from a family member or one of the migrants who were locked in the shipping container."
The mayor explained that his information came from the Uvalde Police Department and the Southwest Texas Regional Advisory Council, or STRAC, which medically serves 22 counties in the region. STRAC was the lead agency in the response effort.
He said the medical response was enormous. "There were more people than we had ambulances [currently] available in Uvalde. We called them in from everywhere — Kerrville, San Antonio, Hondo, and locally in Uvalde."
ICE Homeland Security Investigations (HSI) was leading the investigation. It said it was investigating the possibility of human smuggling but wouldn't provide any more details.
The segment of Highway 90 between the border town of Del Rio and San Antonio has become a major human trafficking route.
McLaughlin said that law enforcement in the area have discovered migrants on trains, and they regularly encounter human smugglers in high speed vehicle chases through the area.
"We deal with this every day down here," he said. "Not deaths every day but we're dealing with immigrants every day. Seven days a week."
Last June, 53 migrants were found dead in a tractor trailer in San Antonio.
