A Border Patrol officer and his human/narcotic detector dog were roving through lanes of traffic waiting to enter the U.S. at the San Ysidro port of entry, when the canine alerted the officer to the truck.
When the officer looked closer, he discovered a man and woman hidden under the pickup truck's bed liner in a secret compartment.
The 39-year-old truck driver, a U.S. citizen, was arrested. Both immigrants will be returned to Mexico.
