LAREDO, TEXAS — Six people were found dead inside a Union Pacific cargo train boxcar near a rail yard on the outskirts of Laredo, Texas, on Sunday. Police responded around 3 p.m. to a call from a Union Pacific employee reporting multiple casualties inside a trailer box car.

The boxcar was located on Jim Young Way near Mile Marker 13. Temperatures in Laredo on Sunday reached a high of 97 degrees, according to the National Weather Service.

The ages of the victims and the origin of the train were not immediately released. The Webb County medical examiner will conduct an autopsy to determine the cause and manner of death.

Laredo Police Department Investigator Jose Baeza described the site where the boxcar was found. "Imagine a loading dock at a seaport, but for trains. This is where they load and unload a lot of rail cars." Baeza said the discovery was "At the crux of the ongoing fluid investigation."

A Union Pacific spokesperson addressed the incident in a statement. "We are saddened by this incident and are working closely with law enforcement to investigate."

The investigation into the deaths remains ongoing, and police said more information will be released as it becomes available. Laredo, which borders Mexico, has one of Texas's largest ports of entry facilitating commercial trade. As of 2024, Port Laredo accounted for 62% of Texas's land port trade valued at nearly $340 billion, according to data collected by the Texas Comptroller of Public Accounts.