North Korea’s missile and nuclear programs continue to draw the ire of President Donald Trump and the international community. Harsh economic sanctions are imposed on the country, so where is it making its money? A North Korean defector said a large way is smuggling.

Ri Jong Ho used to work in the high levels of the North Korean government helping the country bring in foreign income until gruesome executions made him want to leave Kim Jong Un’s regime.

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Ri said he decided to leave in 2013 when Kim executed his own uncle with an anti-aircraft gun, according to CNN Thursday. Ri called it “a cruel and crude method of execution.”

“It was not just high-level officers, officials, but their families, their children, their followers,” Ri said to CNN. “It was not just once or twice a year — it was ongoing throughout the year, thousands of people being executed or purged.”

Ri worked in a secretive department of the North Korean government called “Office 39,” which creates a slush fund for its leadership through foreign income.

While Ri said none of the operations the office does are illicit, but the U.S. government and others disagree.

Russian cyber security firm Kaspersky released a report in April saying North Korea was linked to bank hacks in 18 countries. The stolen money could be helping fund North Korea’s missile and nuclear advances. This month, North Korea test-launched two intercontinental ballistic missiles (ICBM), the longest range missiles the country had ever tested. The Union of Concerned Scientists claimed North Korea has the ability to hit many major American cities with their ICBMs.

In 2013, the Drug Enforcement Agency broke up a drug ring in Thailand, with connections to North Korea. The dealers were trafficking extremely pure methamphetamines believed to have been made in North Korea.

Smuggling is another boon for bringing cash into North Korea.

“Smuggling is conducted by any and every means you could imagine. Mostly larger items are done using ships, for example by filing a cargo list ... where what's written … is different from what is really being shipped,” said Ri to CNN. “On the open sea, the Yellow Sea, there are hundreds of fishing boats, both from China and North Korea, and all the smuggling is done by these so-called fishing boats.”

Despite sanctions levied by the U.S. and the United Nations (U.N.) against North Korea, Ri said the government works hard to side step them by actions like changing North Korean company’s names after they’ve been sanctioned.

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Ri explained the best way to go after North Korea is secondary sanctions, especially on Chinese businesses. China is North Korea’s biggest trading partner and accounts for around 85 percent of North Korean imports, according to the U.N. in 2015.

China has made some moves on its own, such as curbing coal purchasing from North Korea in response to Un’s aggressive missile testing, but Trump has grown increasingly impatient with China hoping that they would fix the problem for him.