Six migrants, including a 14-year-old boy, were found dead inside a shipping container at a Union Pacific rail yard near Laredo, Texas, on Sunday afternoon [1, 2, 3, 4]. Authorities believe the victims died from heat-related causes after being trapped for up to eight hours, with one autopsy confirming hyperthermia as the cause of death [1, 2, 3, 4]. Laredo Mayor Victor Trevino said preliminary medical findings indicate the victims likely died of heatstroke several hours before their bodies were discovered [2].

The six included three Mexican nationals and others confirmed or believed to be Honduran [1, 2, 3, 4]. Among the deceased was a 14-year-old boy [2, 3, 4]. Officials are investigating the case as a human smuggling incident. Laredo Police Chief Miguel Rodriguez said authorities believe the migrants were victims of a human smuggling operation [2].

Federal and local agencies involved in the investigation include Homeland Security Investigations, the Laredo Police Department, Texas Rangers, and the Webb County Medical Examiner's office [1, 2, 3, 4]. Authorities are working with the Mexican consulate to identify the victims and assist their families [1, 4].

The shipping container was on a train that reportedly departed Long Beach, California, on May 7. It arrived in Del Rio, Texas, on Saturday, where migrants are believed to have boarded the container [2, 3]. Dr. Corinne Stern, the medical examiner, said, "I’ve ruled that an accidental death. Based on my examination on the scene and what I know of from the investigation, I really believe they were dead in less than eight hours" [1].

A seventh body was found near railroad tracks outside San Antonio, about 150 miles from Laredo, which may be connected to these deaths [1]. Bexar County Sheriff Javier Salazar noted that some train containers have sensors alerting authorities if they are opened during transit [1].

The investigation continues into exactly how the migrants were smuggled and died inside the container. Autopsies for the other victims remain ongoing. Authorities have not released additional details on suspects or arrests.