The Chinese graduate accused of being Mexico’s ‘fentanyl king’

“Brother Wang was very important. He was number one,” Enrique says with a knowing chuckle.

Enrique (not his real name) describes himself as a high-level coordinator in Mexico’s Sinaloa cartel, one of the most powerful criminal organizations in the world.

Sitting in a parked car on the outskirts of Culiacán, the capital of Sinaloa state, where no one can hear him, he describes how the ingredients needed to make the deadly drug fentanyl were shipped from Chinese factories to laboratories thousands of miles away in Mexico. Members of his cartel credit Brother Wang with establishing this supply chain.

Brother Wang, known as the “fentanyl king” in the criminal world, is a 39-year-old Chinese citizen whose real name is Zhang Zhidong, according to the US Department of Justice. Arrested in Mexico in 2024, Zhang made a dramatic escape before being recaptured and extradited to the United States in 2025.

Fentanyl is a synthetic opioid that is 50 times more powerful than heroin. It kills tens of thousands of people every year, mostly in the United States, where the finished drug often ends up. A dose as small as a few grains of salt can be lethal.

U.S. President Donald Trump has labeled fentanyl dealers “narco terrorists,” classified the drug and its components as weapons of mass destruction, and used the fentanyl trade as a reason to impose tariffs on China, Mexico, and Canada.

When Zhang appeared in court in New York in 2025, then-Deputy Attorney General Todd Blanche described him as one of the “world’s most dangerous human traffickers.”

He also accused him of “running a global company that pumped massive quantities of cocaine, fentanyl and methamphetamine into the United States” and laundering “millions of dollars in narcotics proceeds.”

Zhang has pleaded not guilty and is currently awaiting trial. We contacted his attorney, who declined to comment while the case is ongoing.

Cartel members and former colleagues agreed to speak to the BBC to give a rare insight into how they believe Zhang, a graduate of China’s most prestigious university, became a key link in the chain between Chinese chemical manufacturers and Mexican pharmaceutical laboratories.

Adam Zhang

Zhang graduated from the prestigious Peking University in Beijing in 2010 with a degree in Spanish and a year later went to Mexico to work for a Chinese company mining iron ore. He soon secured a senior role.

Those who knew him at the time saw him as a bright young professional eager to live abroad.

“He had the ability to negotiate with people, was very resourceful, and could adapt to any environment,” says Alex (not his real name), who studied at the same university as Zhang in Mexico and later worked for the same mining company.

He says Zhang speaks excellent Spanish, is fluent in street lingo and can talk to anyone, always speaking with a strong Beijing accent.

Alex says doing business in Mexico sometimes requires dealing with the underworld, including the cartels that control key parts of the country. Alex says Zhang was able to build relationships with “everyone who mattered locally – both the official and unofficial side.”

Zhang loved this aspect of Mexico, according to Alex, who painted a picture of a man drawn to risk and recklessness. He remembers crashing his boss’s car, uncaring of the repercussions, and describes how Zhang took him out of town one night to shoot a gun at road signs on a deserted highway.

In 2013, the mining company collapsed and Alex returned to China but Zhang remained in Mexico.

A year or two later, Alex says, Zhang started offering to exchange dollars at preferential rates to a group of Peking University Spanish alumni on WeChat. Alex believes he is laundering money.

Additionally, cartel member Enrique says Zhang was also involved in drugs. U.S. court filings accuse Zhang of operating a “major narcotics trafficking and money laundering organization” since June 2016.

Enrique believes that Zhang became romantically involved with a female relative of one of the cartel leaders, suggesting that this helped him become closer to the cartel’s inner circle.

supply chain

Luis — not his real name — another cartel member who runs errands for the organization, recalls a hot afternoon in 2019 when his bosses asked him to stand guard for a meeting where Zhang “came to present his products.”

Luis says these products are the precursors (chemical building blocks) necessary for the production of fentanyl. He credits Zhang with effectively introducing him to fentanyl and initiating this aspect of the group’s business.

Luis soon reveals that he is a fentanyl cook and is making the drug in a secret laboratory. He says he saw at least five other cooks die before his eyes, and he believes it was because the substances they used were leaking through gaps in their protective clothing.

“Sometimes people faint and we have to carry them out of the room,” he says.

Enrique explains how to place orders for precursors to Zhang, who he says used his contacts in China to secure the chemicals.

The materials will then be shipped to Mexico by air or sea, according to Enrique. He said his network would then distribute them to fentanyl cooks like Luis at illegal labs in Sinaloa.

When asked if he felt guilty for being involved in an industry that caused so many deaths, Enrique said one of his relatives died of a fentanyl overdose. “It shakes your conscience,” he says, but adds: “Business is business, and we don’t know any other way to make a living.”

When asked the same question, Luis said he once tried to quit working in the lab, but his boss told him the alternative was to go on patrol. He says his boss gave him a choice: “You put on your vest and gear and go out and fight; it’s either that or work as a cook.”

According to Mexican security agencies, Zhang was conducting illegal operations spanning the United States, Europe, China and Japan.

Victoria Dittmar, a researcher at InSight Crime, a think tank, has spent years investigating the flow of precursor chemicals into Mexico. He says brokers, the role Zhang is alleged to have played, are at the critical intersection between chemical manufacturers and cartels.

He says people with the kind of access Zhang is said to have are “pretty unique” and “key to the supply chain.”

“He was a broker who connected Mexican smuggling organizations to leading Chinese chemical suppliers,” a world he says is difficult for outsiders to navigate.

“He also had a big presence in the United States,” he says. “You don’t see that very often… one person who can connect three regions.”

Mexican authorities said Zhang was responsible for the export and distribution of more than 1,000 kg of cocaine, 1,800 kg of fentanyl and 600 kg of methamphetamine. They also accused him of handling drug proceeds of more than $150 million annually.

The US Department of Justice issued a press release in 2025 detailing the indictment against Zhang. In addition to accusing Zhang of drug trafficking, it was also stated that he recruited people to open bank accounts in the names of more than 100 shell companies.

It says they would collect money from various locations in the United States, “deposit that money into the shell company’s bank accounts, and transfer the funds to other beneficiary accounts to be laundered outside the United States.”

At the other end of Zhang’s alleged operations is China. The country is one of the world’s largest producers and exporters of precursor chemicals used to make synthetic drugs, according to a 2025 report by the U.S. State Department.

China’s chemical industry is “huge” with 160,000 companies, he says, and oversight remains “understaffed and equipped” despite authorities’ steps to impose controls.

The Chinese embassy in Washington told the BBC that China was “one of the toughest countries in the world when it comes to countering narcotics.”

He noted that the country scheduled all fentanyl-related substances in 2019, which means they are tightly controlled by the government. Some have legitimate uses across multiple industries and are not banned.

The embassy said China’s “comprehensive and in-depth” cooperation with the United States in countering narcotics has been “extremely productive.”

Escape and arrest

Zhang’s alleged involvement in the drug trade came to an abrupt end with his arrest in Mexico on October 31, 2024.

A judge made the controversial decision to place him under house arrest, but Zhang managed to escape, reportedly through a hole in the wall, and escape by private jet to Cuba and then Russia.

Russian border officials detected his forged documents and he was sent back to Cuba, which then sent him back to Mexico, from where he was extradited to the United States.

His arrest made headlines around the world. The alumni network of Beijing Peking University, where Zhang studied Spanish, was stunned.

“Everyone was talking about it,” says Alex. “It was a very shocking story, and he was probably one of the most famous people ever produced by Peking University.”

In Culiacán, cartel members say Zhang’s absence was felt immediately.

Luis says it’s “becoming really difficult to recruit pioneers.”

“They took the guy and it caused chaos,” says Enrique. He said Zhang was “someone with connections” in China and that the cartels needed to “start from scratch and build a new route.”

Around the same time, the United States Drug Enforcement Administration began detecting a decline in fentanyl purity, which it said was “consistent with indications that many Mexico-based fentanyl cooks are having difficulty obtaining some key precursor chemicals.”

But disruption to pharmaceutical supply chains is often temporary, in what Dittmar describes as “a constant game of cat and mouse.”

His research tracked how fentanyl producers adapted by finding substitutes and learning new processes when middlemen were removed or key chemicals were brought under control.

Individuals in the supply chain are also replaceable; even those as deeply and widely connected as Zhang allegedly was, according to cartel members.

Enrique says there is already another Chinese man in the frame, but says he can’t say more “for my own safety.”

Another cartel member, who describes himself as a coordinator responsible for the transportation of goods and personnel within the cartel, says, “All this started because of him.” [Brother Wang]…he left many connections to help us continue”.

“If he leaves, someone else will step in… the work will not stop.”

Additional Reporting by Ruth Evans and Miguel Angel Vega