Extreme heat is suspected to have played a role in the deaths of six people from Mexico and Honduras whose bodies were discovered inside a train car in Laredo.

A 29-year-old woman from Mexico and a 24-year-old man from Honduras were among the six deceased individuals found inside a shipping container at Union Pacific Railyard on Sunday afternoon, according to Webb County officials. The other four individuals were all male and included one teenager, though their identities had not yet been confirmed.

The Webb County Medical Examiner determined that the woman died due to hyperthermia, or overheating. Hyperthermia is also suspected to have caused the death of the other five individuals, though formal examinations for them are still pending, according to a news release issued by the county.

Corinne Stern, the county’s medical examiner, found identification cards and cellphones that indicated the individuals were from Mexico and Honduras, according to the Associated Press. Their fingerprints were also shared with the U.S. Border Patrol to help confirm their identities and nationalities through the Missing Alien Program.

The medical examiner’s office is also working with the Mexican Consulate to confirm the identities of individuals, notify their families, and repatriate their remains.

Laredo Mayor Victor D. Trevino issued a statement lamenting the deaths, which he called a “tragedy.”

“In our close-knit binational community, every loss is felt deeply,” Treviño said. “Our hearts are with the families and loved ones affected, and we thank our first responders for their efforts during this difficult time. Our community stands united in prayer and compassion.”

The six people were discovered at approximately 3:30 p.m. on Sunday in a Union Pacific train boxcar. It is unclear where the train’s route originated or when the individuals boarded the train.

Union Pacific did not respond to questions but issued a statement saying the company “is saddened by this incident and is working closely with law enforcement to investigate.”

Migration to the U.S. continues to be a high-risk endeavor.

Immigrant deaths are a common occurrence for the Webb County Medical Examiner’s office, which serves 11 counties on the South Texas border, Stern told the AP.

“This spring has been busier than it was this time last year,” she said.

In 2025, at least 131 people died along the U.S.-Mexico border, according to the International Organization for Migration. About 15% of those cases were due to extreme environmental conditions and lack of access to water, food, and shelter.

In 2022, 53 people from Mexico and Central America died after being transported in a sweltering tractor trailer the driver abandoned in Southwest San Antonio.

In that case, considered by officials to be the deadliest migrant smuggling case in U.S. history, 64 migrants were packed into the trailer without water or air conditioning, on a June day that reached 100 degrees.

Federal prosecutors indicted two Texas men over the deaths. Both of them pleaded guilty and await sentencing.

Alex Nguyen contributed to this story.

This article first appeared on The Texas Tribune.