SAN ANTONIO (AP) — A police official in Texas says 29 people have been recovered from a big rig that was stopped near San Antonio, including one person who was taken to a hospital.

Lt. Jesse Salame says a passerby called police to report a suspicious semi-truck.

An officer performed a traffic stop and as he was approaching the vehicle, the back door swung open and several people ran out.

Police made contact with 29 of the people.

One person was taken to the hospital to be treated for dehydration.

U.S. Immigration and Customs Enforcement said in a statement that the traffic stop is being investigated for possible human smuggling.

According to The Associated Press, the semi-truck driver, 49, was taken into custody.