More than 500 pounds of pot found stuffed in farming equipment was seized at the Presidio border.
The haul was discovered by U.S. Customs and Border Protection agents on Tuesday afternoon when a semi pulling a flatbed loaded with six used farm tractors was crossing over.
After an x-ray, officers found 567 pounds of marijuana hidden in the tractor tires.
It's still under investigation. So far no arrests have been made.