EAGLE PASS, Texas (AP) — A Texas Department of Public Safety officer has died after being involved in a single vehicle traffic accident near the U.S.-Mexico border while working with the U.S. Border Patrol.

Special Agent Anthony Salas was helping transport six individuals who had illegally immigrated to the U.S. when the accident took place Friday evening near Eagle Pass, according to U.S. Customs and Border Protection.

Salas was initially taken to a hospital in Eagle Pass and then transported to University Hospital in San Antonio, located about 140 miles (225 km) to the northeast. Salas, 37, died Saturday morning, the Texas Department of Public Safety said in a statement.

“This tragedy is a somber reminder of the selfless sacrifices our law enforcement make as they work to keep us safe,” Gov. Greg Abbott said in a statement.

Salas, who joined the department in 2013, had been stationed in El Paso. He served as a trooper with the Texas Highway Patrol before being promoted to a special agent in the department’s Criminal Investigations Division. He was a member of the DPS West Texas Special Response Team.

The Texas agency and Customs and Border Protection’s Office of Professional Responsibility are investigating the accident.