Cocaine and meth cemented inside boulders at the Tecate cargo crossing. Courtesy U.S. Customs and Border Protection

U.S. Customs and Border Protection officers at the Tecate cargo crossing had to break open boulders on Monday to find 229 packages of methamphetamine and cocaine hidden inside, according to the agency.

At about 10:45 a.m. on Sept. 14, a truck driver arrived at the Tecate border crossing with a shipment listed on the trucking manifest as multiple tons of beach pebbles and stones. The CBP officer completing the inspection for entry to the U.S. referred the driver, truck, and shipment to the dock.

At the dock, a CBP officer noticed discrepancies with the shipment. A CBP canine team screened the shipment, which resulted positive for narcotics.

Officers searched the truck, tractor-trailer, and cargo containing various rocks, and ultimately had to break open the large quartz boulders that were part of the shipment. Inside, they found packages wrapped with black electrical tape, which had been cemented inside of the stones.

In total, the agency reported officers found 229 packages concealed inside the large rocks resulting in 104 packages of methamphetamine and 125 packages of cocaine. Combined, the approximate 337 pounds of methamphetamine and 223 pounds of cocaine have an estimated street value of almost $3.9 million.

CBP officers seized the tractor-trailer, shipment, and narcotics.