The seizure at the Otay Mesa Port of Entry late Friday totaled 19,957 pounds and smashed the previous record for a marijuana interception at the Mexican border of 15,185 pounds set in 2001.
"We get a lot of false bottoms, false trailers, deeper concealments in the trailer, the tractor or in the cargo itself," Customs spokesman Nat Aycox told The San Diego Union-Tribune. "In this particular case, the contraband was the cargo."
A 39-year-old Tijuana trucker was arrested after the dog alerted on the truck's trailer and agents began opening the stacks of television boxes inside which bales of marijuana were allegedly stashed. He was being held in San Diego Monday pending arraignment in federal court.
Aycox told the newspaper it was law enforcement instincts rather than a tip that prompted agents at the busy commercial crossing to waive the truck was waved to the secondary-inspection lane.
"This is what we call a cold hit," Aycox said. "There was no (advance) intelligence on it at all."
Otay Mesa is located a few miles east of the busy San Ysidro border crossing between San Diego and Tijuana. Around 770,000 trucks pass through the port of entry annually, making San Ysidro the second-busiest cargo port on the border behind Laredo, Texas.
Aycox said vehicles of all types have been getting closer scrutiny due to the heightened national security alert. Customs officials last week credited the "Condition Orange" with a 62-percent increase in the volume of drugs seized along the Texas-Mexico border, including 2,752 pounds of marijuana, 209 pounds of cocaine and other narcotics with a total estimated value of $6.6 million.