Slumping demand for Mexican "brick weed" has more drug farmers turning to growing opium poppies for heroin production. Here, Mexican soldiers stand amid poppy flowers and marijuana plants during an operation at Petatlan hills in Guerrero state, Mexico on Aug. 28, 2013. (Pedro Pardo, AFP/Getty Images)

New drug dynamic for Mexico-U.S.: Less pot, a lot more heroin, meth

Heroin and meth are far easier to transport and conceal than marijuana. Especially worrisome to U.S. officials is a growing trend of more border-crossing pedestrians carrying the drugs strapped under their clothing or hidden in body cavities.

“The criminals are trying to blend in among the legitimate travelers, who are 99 percent of the individuals crossing through here,” said Aki, the San Ysidro port director. “That’s the hard part for us.”

At the San Ysidro crossing, soon to expand to 35 lanes, U.S. agents with drug-sniffing dogs and foot-long screwdrivers weave among the lines of cars that back up into Mexico.

Agents say the screwdrivers, some so old their handles are worn to a nub, are their most valuable investigative tool. Agents knock them against tires and gas tanks for a quick sonic impression.

“If you tap a tank with something solid inside, there’s a thud,” one inspector said. “It’s like hitting concrete.”

Harder to detect are “deep-concealed” drugs buried in fake engine cylinders, dashboard panels, even acid-proof capsules inside car batteries. One vehicle seized here last year carried liquid meth in its windshield-wiper reservoir.

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Finding small packages in the river of cars and trucks coming across is akin to a game of “Where’s Waldo?” for U.S. inspectors. Vehicles that arouse the suspicions of border agents or get their dogs barking and lunging are sent to a secondary inspection station with giant X-ray machines and larger teams of screwdriver-wielding inspectors.

If drugs don’t appear, the agents may drive the vehicles into garages to open their engines, pry apart interior panels and search for any signs of suspicious alterations. Traffickers will sometimes mist decoy vehicles with marijuana oil or resin to provoke the dogs and draw agents into a fruitless search.

“It’s like a fish fry,” Aki said. “The fish is gone, but the scent is still there.”

With the dogs and agents tied up inspecting the decoys, the traffickers may try sneaking meth and heroin through.

In recent years, Mexican cartels also have begun producing higher-value “white” heroin, typically associated with traffickers from Colombia or Asia, according to DEA officials.

“The Mexicans are evolving in their production abilities and getting more sophisticated,” said Payne, the DEA spokesman. “It’s not just black tar anymore.”

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Colombian and Caribbean traffickers once controlled heroin distribution east of the Mississippi River, but Mexican criminal groups now dominate the entire North American market, he said.

The United States has an estimated 600,000 heroin users, Payne said — a threefold increase in the past five years. But that number is dwarfed by the estimated 10 million Americans who abuse prescription painkillers.

Those addicts are the prime target for the booming heroin business. A U.S. crackdown on prescription opiates has driven up the price for drugs such as OxyContin and Percocet, enticing desperate addicts to switch to cheap heroin to fend off withdrawal symptoms.

The profile of U.S. heroin addiction is also changing, said Phil Herschman, chief clinical officer with the CRC Health Group, which operates 170 treatment centers in 30 U.S. states.

“Now, we’re seeing housewives coming in who had been addicted to Vicodin for two or three years before switching to heroin, or adolescents who got hooked by snorting it, thinking it was safe, only to end up injecting themselves,” he said.

“You can’t even begin to measure how it tears families apart,” he added. “It’s devastating.”