The cruel fate that awaits top North Korean officials who fail or disappoint the North’s leader, Kim Jong-un, emerges in harsh detail in an exclusive interview with a high-level diplomatic defector in South Korea’s biggest-selling newspaper, Chosun Ilbo.

The defector, former counselor of the North Korean embassy in Havana, Ri Il-gyu, told the paper the vice foreign minister, Han Song-ryol, was publicly executed in February 2019 after the failure of Mr. Kim’s summit in Hanoi with President Trump. He was accused of spying for the Americans, an easy pretext for getting rid of someone who has incurred Mr.Kim’s wrath.

In Cuba at the time,  Mr. Ri said senior foreign ministry officials, ordered to watch the execution at a military academy near Pyongyang’s airport,  “reported being unable to eat for several days.” Ten months later, in December 2019, the former foreign minister, Ri Yong-ho, “was accused of corruption, leading to his entire family being sent to a prison camp.” 

That case exposed embezzlement at the North Korean embassy at Beijing, where Ri Yong-ho and other high-ranking officials were found to have accepted bribes.  “Furious,” Mr. Kim criticized Ri Yong-ho “for half a day” at the plenary meeting of the central committee of the ruling Workers Party, Ri Il-gyu told Chosun Ilbo.

Disclosures of the fate of Han and Ri Yong-ho, both well known to American diplomats negotiating the summits between Mr. Kim and President Trump, first in Singapore in June 2018, then in Hanoi, shed new light on the vindictive nature of the Kim regime and the high risks of crossing him.

The personal saga of Mr. Ri, former counselor of the North Korean embassy in Havana, is just as intriguing for what it says about survival in a corrupt, class-oriented bureaucracy. “North Korea has no hope under Kim Jong-un’s regime,” the headline quotes him as saying.

South Korea’s National Intelligence Service  confirmed that the 52-year-old ex-diplomat had defected eight months ago, apparently by flying to Seoul from Havana four months before Cuba’s Communist regime, long a staunch North Korean ally, formed relations with anti-Communist South Korea.

As North Korea’s man in Havana, Mr. Ri fled to freedom with his  family after having failed to stop Cuba from forming diplomatic relations with South Korea. Mr. Ri exposes “reality” is how Chosun Ilbo prefaced the interview, which begins with Mr. Ri denouncing  Mr. Kim’s “anti-reunification two-state policy” as “an act that obliterates the soul of the nation.” 

Personal reasons, as much as ideological and political differences, accounted for the defection “The direct cause was the unfair evaluation of my efforts, leading to frustration and anger,” he’s quoted as saying in Chosun Ilbo’s translation for its English-language website.

North Korea’s foreign ministry “is full of people from powerful families,” he explained. “My background is classified as ‘clerical,’ which is less favorable compared to ‘worker’ or ‘soldier.’ I started at the lowest rank and worked diligently.”

Nearly five years ago, however, when Mr. Ri  asked about opening a North Korean restaurant in Cuba, an official in Pyongyang demanded a significant bribe, he said.  Mr. Ri’s response, “Let’s discuss it later,” led to “resentment and attempts to recall me” — and “harsh evaluations of my work.”

Mr. Ri’s defection  was the latest in a series of high-level North Korean diplomatic flights to freedom — the chief of the North’s embassy in Kuwait and its ambassador to Italy defected in 2019. The North’s deputy ambassador to Britain, Tae Yong-ho, fled London with his wife and two sons in 2016. Elected to the South’s National Assembly in 2020, he served four years before his defeat in April’s elections.

South Korea’s Yonhap News quotes Mr. Tae as welcoming Mr. Ri, calling for former North Korean diplomats in South Korea to “work together for reunification to make North Korean officials’ and residents’ dreams come true for their children to live freely in the Republic of Korea.”

Mr. Ri, given a commendation by Mr. Kim for having negotiated the release in 2013 of a North Korean vessel held in the Panama Canal after missiles and parts for fighter jets were found on board, described having tea with the leader.

“In person, Kim Jong-un is just an ordinary human,” he told Chosun Ilbo. “Up close, you can’t help but think his blood pressure must be extremely high; his face is always red like he’s been drinking, even redder than on screen.”