Three people found in the trunk of a car by the California border patrol

PINE VALLEY, Calif. -- Border Patrol agents say they found three people in the trunk of a car at a Southern California checkpoint.

Authorities say the Volkswagen Jetta stopped at the Pine Valley checkpoint in eastern San Diego County on Saturday.

A trained dog alerted agents, who searched the car and found two women and man in the trunk. Authorities say the three, who ranged from 19 to 28 years old, were Mexican citizens.

They were sweating from the high temperature and lack of ventilation.

The car's driver and passenger - both U.S. citizens - were arrested and face federal charges of human smuggling.

Three people were found in the trunk of another car at the same checkpoint about three weeks ago.