Confessed to Killing Two Children Then Recanted: Decoded Ciphers Reveal 'Child Grooming'

Is Ma truly the culprit behind the serial disappearances of elementary school girls?

Aired yesterday (October 17), SBS's 'Unanswered Questions' traced a prime suspect in the serial disappearances of elementary school students, a cold case that has remained unsolved for 26 years.

In June 2000, Kim Seong-ju, a second-grade elementary school student, vanished without a trace in Gangjin, South Jeolla Province, while waiting for her older brother after school. Exactly one year later, on June 1, 2001, first-grader Kim Ha-eun also disappeared on her way home from school, just 1 kilometer away from where Seong-ju was last seen.

The consecutive disappearances occurring within a single year sent shockwaves through the small county of 18,000 residents. At the time, authorities suspected kidnapping or human trafficking, but no ransom demand or threatening call was ever received from the perpetrator.

As time passed, police zeroed in on Ma, who was in his early twenties and residing in the area at the time, as a prime suspect. In 2010, while under investigation by prosecutors for a separate child sexual offense, Ma confessed to killing both missing children and abandoning their bodies.

He even accompanied investigators to the crime scene reconstruction, but was never formally apprehended as a suspect in the disappearances. No substantial evidence emerged during the reconstruction, and Ma subsequently recanted his confession.


Ma was also convicted of murdering his ex-wife's younger brother. His ex-wife gave a statement claiming she had seen a videotape containing sexually exploitative footage of a girl believed to be Ha-eun. However, the videotape was never recovered, and Ma walked away free from charges in the disappearance cases.

Sentenced to 15 years in prison for murdering his brother-in-law, Ma faced renewed scrutiny when police decided to investigate him directly, summoning him multiple times. However, he consistently refused questioning. In the process, unintelligible ciphers were discovered inside his prison cell. Even the National Forensic Service failed to crack them.

Detective Choi, who was investigating with the cold case missing persons squad, finally deciphered the code. Rather than containing confessions about his crimes, it was a message celebrating his creation of a personal cipher system.


Following his release from prison, Ma was sentenced to another eight years for sexually assaulting a woman with intellectual disabilities. Through that case, approximately 200 pages of his encrypted notes were uncovered.

The cipher system had grown far more intricate. Detective Choi spent an entire month deciphering the documents. Shockingly, the decoded writings—which listed things Ma wished to do upon his release—contained expressions such as "child grooming," "making children engage in sexual acts with each other," "filming pornography," "letting them experience orgasm, God's greatest gift, at as young an age as possible," and "having sexual relations with my daughter if she is born."

The production team tracked down Ma, who was released from prison in September of this year. He drew attention by appearing in an unusual outfit.

Showing off his electronic monitoring ankle bracelet, Ma remarked that he had expected the broadcast network to seek him out, and began recounting the murder of his brother-in-law. He claimed that his divorce had been prompted by incest involving his ex-wife and brother-in-law, and insisted that the murder of his brother-in-law was driven by his schizophrenia.

He also grew agitated when asked about the videotape, dismissing it as an absurd fabrication. Although Ma initially agreed to an interview, he abruptly changed his mind, stating that asserting his innocence would yield him nothing.


Ma subsequently became difficult to reach. However, once previews for the broadcast about him were released, he contacted the team a few days later, offering to sit down for a formal interview.

Appearing dressed in women's clothing, Ma opened up, claiming he wanted to set the record straight. Regarding the children who vanished in the serial disappearances, he said, "I have never seen them, nor have I ever known them."

Regarding child sexual abuse victim Park Jin-ho, Ma claimed he had merely touched the child's chest. He also denied any knowledge regarding the claim by the older sister of missing child Ha-eun that she had once visited his home to play.

Furthermore, he claimed, "All of the police's evidence is just fabricated to frame me as a suspect," adding that the same applied to the videotape.

He asserted that the ciphers were merely a meaningless prank designed to evade prison guards' censorship, and claimed that his writings on deviant sexual desires and abnormal urges toward young girls were "simply quotes taken from a book." However, no such content was found in the book Ma cited.

When asked about the phrase "Brilliant Kingdom, Incest Special City" in his cipher, Ma offered an incomprehensible worldview, stating, "A human being can be a universe in themselves, or a nation in themselves. In this single body, this part is the command center and the rest is the system running that nation." He added, "'Incest Special City'—things like that are not important. Being alone was boring, so I just wrote provocative phrases."


Ma, who had previously searched for information on the serial disappearances and the statute of limitations on a computer at a public bathhouse, claimed, "Even if it was not my crime, I could still get dragged into it, which is why I looked it up." He also claimed that his earlier confession to murdering the missing children was a false confession forced out by investigative coercion.

However, an expert analyzed: "Failing to actively and directly deny one's allegations is unusual. His logic is, 'Where is the evidence? Without evidence, I am innocent.'" The expert added, "Would any criminal confess additionally to kidnapping and murdering two children simply out of fear of a heavy sentence for sexual assault? It makes no sense. It is merely an excuse; judging by his statements alone, the probability that this person is the culprit is high."

Another expert said regarding Ma's claims of schizophrenia, "This is not schizophrenia, but a textbook manifestation of a psychopath: egocentrism, an inability to suppress impulses, a lack of remorse or reflection after wrongdoing, and an utter absence of empathy."

The expert also pointed out, "He has an exceptionally high need for control. Even during an interview, he has a narrative he wants to push, and when faced with unexpected questions or refutations, he becomes emotionally agitated and even resorts to violence."

"Crimes committed against children or women with intellectual disabilities are closely tied to a controlling nature," the expert added. "Pedophilia is an entrenched, malicious pattern that persists over long periods and can produce dozens or even hundreds of victims. Therefore, there may be dozens more victims beyond those currently identified in statements."


At the time of the serial child disappearances, Ma was driving a vehicle with stolen license plates. An expert pointed out, "He prepared this in advance to pin his crimes on the license plate owner. This could serve as a critically important clue."

However, Ma dodged questions about the vehicle and stolen plates, stating, "Everything you're asking right now is useless. It's all just suspicion."

Detective Choi expressed hope that the cold case could finally be cracked, saying, "In the statement of grounds for appeal regarding the abduction and enticement of the woman with intellectual disabilities, the prosecutor noted that during the Park Jin-ho investigation, Ma had openly spoken about murdering two girls and secretly burying their bodies. The prosecutor wrote that he was unable to indict only due to a lack of corroborating evidence. While evidence was lacking back then, a massive volume of material has accumulated since. These could serve as corroborating evidence."

A legal expert also raised expectations for solving the long-unsolved mystery, stating, "If prosecutors or investigators testify in court and prove that Ma gave his confession voluntarily and in a credible state of mind, punishment could indeed be possible." 

(Editor Kim Hyo-jung)
※ Please note: This article was translated by AI and may contain errors.