SAN ANTONIO — More than two dozen people were recovered from a big rig that was stopped near San Antonio, including one person who was taken to a hospital, a police official in Texas said.

A passerby called police Thursday to report a suspicious semitruck along Interstate 10, east of San Antonio, Lt. Jesse Salame told reporters. A San Antonio Park police officer initiated a traffic stop.

As the officer approached the vehicle, the back door swung open and several people ran out, Salame said. Authorities made contact with 29 of the people who had been in the semitruck.

One person was taken to the hospital to be treated for dehydration, San Antonio Fire Department spokesperson Joe Arrington said.

The traffic stop is being investigated for possible human smuggling, U.S. Immigration and Customs Enforcement told KSAT-TV in a statement.

The driver of the truck, described only as a 49-year-old, was taken into custody, Salame said.