Retired Colonel Cheong Kyu-phil during a Korea Times interview in Seoul, May 8 / Korea Times photo by Shim Hyun-chul

Retired Colonel Cheong Kyu-phil's life was shrouded in secrecy until March 2019 when he retired from the military after completing 37 years of service and transitioned to civilian life. During his military career, he served as both a covert agent and military attaché at South Korea's mission in China.

Cheong undertook numerous clandestine operations, commonly referred to as "black ops" within the intelligence community, during which he gathered intelligence about North Korea.

Everything he did at work was classified, known only to Cheong himself and his unnamed boss at the Korea Defense Intelligence Command (KDIC).

Few Koreans are aware of the KDIC, and some have never even heard of it.

The KDIC, a military intelligence agency tasked with conducting clandestine operations related to North Korea, is intentionally kept secret from the public. Unlike civilian intelligence agencies, the KDIC does not have a website because all information about the organization is classified. Basic details such as the number of staff employed and the nature of their work remain unknown.

The KDIC's strict adherence to secrecy has recently faced challenges, as Cheong became embroiled in a legal battle following his retirement from the military. He was falsely accused of espionage, blamed for selling dozens of military secrets to Chinese and North Korean officials — an allegation he deemed ridiculous.

“Frankly speaking, I didn’t understand what was going on because I had never imagined I would face an allegation like that,” he said during a recent interview with The Korea Times. “But I was confident that such a misunderstanding would go away soon, because I didn’t live a life like that.”

However, events took an unexpected turn.

While the espionage charge was cleared, he was indicted and tried for another crime — violations of the Military Secrets Protection Act.

The retired colonel, now 60, has spent the last five years working with his lawyer to prepare for the legal battle and attending trials. A district court ruled against him and a higher court upheld this decision. He is currently awaiting the final ruling from the Supreme Court, which is expected on May 17.

He said he has experienced an emotional rollercoaster over the past five years.

“At times, I have experienced sudden waves of complex emotions. I felt upset and gripped by deep sadness,” he said. “What was most difficult for me to endure was the bitterness I felt when I faced sarcastic reactions from people who were close to me. They gave me the cold shoulder and brushed me off. Some even gossiped about me behind my back. I had thought they would be the last people to turn their back on me, but I was wrong.”

He said he lost 20 kilograms after being accused of espionage.

Retired Colonel Cheong Kyu-phil / Korea Times photo by Shim Hyun-chul

His life was disrupted on May 21, 2019, when around two dozen agents from the National Intelligence Service (NIS) made an unannounced visit to his apartment in Bundang, approximately 20 kilometers south of Seoul.

One of the agents presented Cheong with a warrant, demanding his cooperation in searching his home. This occurred a day after he returned home from visiting his newly-wed daughter in Canada, leaving him still affected by jet lag. Uncertain about the situation, Cheong ushered them in and allowed them to proceed with their searches, which lasted over 24 hours.

The case was transferred to the prosecution as the NIS does not have the authority to directly indict individuals it investigates.

After examining the evidence seized by the NIS, the prosecution concluded that there was no evidence to support Cheong's involvement in the espionage case. In February 2020, Cheong was cleared of the espionage charge. However, on the same day, the prosecution indicted him for another violation of the Military Secrets Protection Act. According to the prosecution, Cheong was accused of unauthorized possession of military secrets, as well as gathering and searching them, which is illegal. This conclusion was based on the results of forensic investigations of a seized floppy disk, where investigators found several deleted files containing classified military secrets.

Cheong dismissed the allegation as nonsensical, arguing that if he were guilty, then all Koreans who use computers for work would also be considered guilty.

He explained that some of the classified files in question were ones he compiled himself during his tenure as a military attaché at the South Korean embassy in Beijing. These files were produced in 2013 and declassified a year later, he said, arguing that the prosecution's claim is baseless.

Lee Myung-hyun, Cheong’s attorney, highlighted two key issues with the prosecution's indictment of Cheong. First, he claimed that the prosecution charged his client with an offense that was not specified in the warrant. Secondly, he argued that the accusation of violating the Military Secrets Protection Act was based on flawed evidence.

“The search and seizure warrant issued by the court in 2019 was specifically intended to allow the NIS staff to find evidence related to the allegation that my client sold military secrets to Chinese and North Koreans,” he said.

But, he said they did not discover any evidence that could substantiate the alleged espionage crime. The lawyer also explained that the NIS conducted computer forensics investigations and uncovered several files that had been deleted many years ago. He argued that the presentation of these "non-existent" files as evidence of Cheong's supposed violations of the Military Secrets Protection Act was problematic.

“Deleted files cannot be used as evidence in a courtroom. This is because those files no longer exist, but the investigators detected them through forensic investigations and presented them as evidence. So, their conclusion based on this flawed evidence doesn’t establish my client did something illegal,” he said.

However, the court sided with the prosecution.

The district court initially ruled against Cheong, sentencing him to a six-month jail term suspended for one year. Cheong appealed the ruling. The higher court upheld the lower court's ruling, but imposed a tougher verdict, sentencing Cheong to a 10-month jail term suspended for two years. Cheong also appealed that ruling. The Supreme Court is scheduled to rule on the case on May 17.

Retired Colonel Cheong Kyu-phil poses with his colleagues at the Headquarters Intelligence Detachment, a special forces tasked with black operations, in this 2015 file photo. This photo was edited to protect the identities of the covert agents. Courtesy of Cheong Kyu-phil

The years-long legal battle has not only taken a toll on Cheong's personal life, but also on his former workplace, the KDIC. If the Supreme Court upholds the higher court's decision, Cheong will lose all financial benefits, including his pension. Additionally, he will be required to repay all financial benefits he has received from the government since retiring from the military.

The KDIC also faced repercussions from the legal battle.

Cheong's identity as a former undercover intelligence agent in northeastern China and his clandestine operations as a military attaché at the South Korean embassy in Beijing to gather intelligence about North Korea were revealed to the public.

People in the intelligence community expressed concerns about the consequences. They said that South Korea’s human intelligence capabilities will be significantly undermined as classified information about the KDIC and its agents was disclosed during the investigations and trials.

“Cheong was considered the best of the best in the intelligence community,” Choe Su-yong, a retired NIS official and director of the private intelligence consultancy, Indo-Pacific Institute in Seoul, told The Korea Times. “He was a legendary intelligence official who contributed a lot to South Korea’s national security. All his work was classified, so we are not allowed to speak to the media in great detail about his contributions.”

Choe, who worked with Cheong at the embassy in the mid-2000s, said the retired colonel was an unrivaled military attache who spoke Mandarin fluently and had a deep understanding of Chinese culture. Cheong also formed a strong network with high-ranking Chinese military officials.

Through that network, he said Cheong was able to gather valuable intelligence information about North Korea, because Chinese officials are privy to sensitive information about the North.

Choe lamented that the legal battle not only harmed South Korea's critical national interests, but also destroyed the life of a patriotic and dedicated military intelligence official who always prioritized his country.

Cheong's trial, which focused on the violations of military secrets, was conducted in a public setting. In the same courtroom, judges handling cases involving sexual harassment, fraud, and other crimes deliberated and ruled on Cheong's case. Defendants of sexual harassment cases and their families were present in the courtroom, awaiting their turns, when the judges ruled on Cheong's case.

An official from the Supreme Court explained that unlike cases involving drugs or other major crimes, there are no specialized judges to handle military secrets. Therefore, cases related to military secrets are overseen by judges who also rule on other offenses, such as sexual harassment.

“This is a case for the Supreme Court,” she told The Korea Times.

Regarding the risks of disclosing classified information related to national security during open trials in civilian courts, she mentioned that the judges of the lower court would have thoroughly considered the sensitive nature of military secrets, indicating that there should be no procedural flaws. "I would prefer not to comment further on this matter as the case is still ongoing," she added.

Retired Colonel Cheong Kyu-phil poses with General Paik Sun-yup in this 2013 file photo taken at an event hosted by ROK/US Combined Forces Command. Paik passed away in 2020. Courtesy of Cheong Kyu-phil

An unanswered question remains regarding the investigation: Why did the NIS take the initiative to investigate Cheong? The NIS is a civilian intelligence agency primarily tasked with espionage investigations back then. In the military, the Defense Counter-Intelligence Command (DCC) is responsible for investigating espionage crimes committed by military personnel.

According to media reports, the NIS initiated an investigation in February 2019 when Cheong was still in the military. This investigation was reportedly based on written testimonies from two individuals familiar with Cheong, although there was no concrete evidence available at that time.

Conspiracy theories have emerged surrounding the investigation. Some allege that the investigation, which began in 2019 during President Moon Jae-in's administration, was part of a politically motivated plot to undermine the military's human intelligence capabilities. These theories suggest that the progressive Moon government was attempting to appease North Korea by targeting certain elements within the military.

Cheong said he has no idea whether the investigation was politically motivated or if it stemmed from a personal attack by someone who envied him.

“Everything remains speculative because there is no concrete evidence to support these claims. Those involved in the investigation have remained silent and withheld information, so there is no way to ascertain why it began,” he said.

This reporter sent a questionnaire to the NIS, inquiring why the civilian intelligence agency did not transfer Cheong's case to the DCC. The NIS declined to comment on the case, citing a law.

"Under the Public Information Disclosure Act, the NIS is not permitted to comment on ongoing criminal cases," the agency informed The Korea Times.

Cheong’s lawyer said things would have turned out very differently if the military reviewed the case.

“If the case had been transferred to the military early on and handled by a military court instead of a civilian court, Cheong might have been cleared without facing indictment,” Lee, who served as a military lawyer for 25 years, said. “Disclosure of classified information about the military intelligence agency would have not happened, either.”

Rep. Yoon Sang-hyun urged the Yoon Suk Yeol government to investigate the NIS to find out why the civilian intelligence agency accused Cheong of espionage.

During a National Assembly plenary session on September 22, 2022, Yoon characterized the case as an attempt by the NIS during the previous progressive Moon Jae-in government to falsely portray a dedicated military intelligence official as a traitor. Yoon pressured Prime Minister Han Duck-soo to initiate a probe to uncover the truth behind why the NIS took such actions.

Han said he was aware of the case, but was not in a position to comment on it due to the ongoing legal proceedings.

“If necessary, the government can conduct a probe into the NIS. However, I am not discussing this specific case. The trial is ongoing, and I believe it would be inappropriate for me to comment on it. I trust that the truth will come to light in due course,” the prime minister said.

The clock is ticking for the Supreme Court's final ruling, scheduled for May 17.

Cheong tried to remain strong.

“I’ve suffered a lot during the past five years. I also learned a lot while going through the tribulations,” he said. “I still don’t understand why I became mired in a case like this, but I think this is also part of life.”

Born in 1964 in the southeastern county of Youngil, which is now part of Pohang, Cheong graduated from the Korea Military Academy and joined the Army's special forces, specifically the Headquarters Intelligence Detachment (HID), a black operations unit reportedly tasked with infiltrating North Korea and targeting key military figures. After completing 37 years of military service, he received a medal from the government in recognition of his lifelong dedication to the military. He was also decorated for his exceptional service and designated as a person of merit.

Retired Colonel Cheong Kyu-phil / Korea Times photo by Shim Hyun-chul