Frog Boys case: Five students vanished in 1991, found dead years later — still no answers

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Frog Boys case: Five students vanished in 1991, found dead years later — still no answers

Published: 23 Jun. 2025, 07:00

CHO JUNG-WOO
[email protected]

Audio report: written by reporters, read by AI

Mug shots of five boys who went missing around 9 a.m. on March 26, 1991. Top row, from left: Kim Jong-sik (9), Kim Young-gyu (11), Woo Cheol-won (13), Jo Ho-yeon (12) and Park Chan-in (10). Above are age-progressed images of what they were anticipated to look like in 1995. [JOONGANG ILBO]

[KOREAN CRIME FILES]

It was a rainy Tuesday afternoon in 1991 when five elementary school boys went missing near Mount Waryong in Daegu. Although it was a weekday, the group was not at school because it was a historic election day, the first in 30 years.

The boys' fathers left their jobs and searched for their sons for years in a truck carrying a large banner with photos of the five, who were between 9 and 13 at the time of their disappearance. Police and military were mobilized nationwide.

And then, in 2002, a hiker discovered their remains.

The father of Kim Jong-sik, right, hands out flyers about the missing Frog Boys to passerbys in an undated photo. [JOONGANG ILBO]

The search begins

On the morning of March 26, 1991, Woo Cheol-won, Jo Ho-yeon, Kim Young-gyu, Park Chan-in and Kim Jong-sik, students at Seongseo Elementary School in Daegu, left their homes to play and never came back.

According to a friend's witness account at the time, broadcast again by SBS's Tails of Tales in January 2024, the boys told a friend they were heading to Mount Waryong to search for salamander eggs. The mountain, which they frequently visited, was relatively gentle, rising just 300 meters (984 feet) above sea level.

The five boys became widely known as the Frog Boys after media outlets mistakenly reported that they had gone in search of frog eggs. Later investigations clarified that they had actually set out to collect salamander eggs.

A little after 1 p.m., Woo Jong-u, the father of Woo Cheol-won, received a call informing him that his son hadn't shown up for his taekwondo class, according to Channel News Asia. He quickly realized that his son and the four other boys were missing.

Parents of the missing Frog Boys look at flyers of their sons in an undated photo. [JOONGANG ILBO]

At first, the disappearance received little media attention, with the nation focused on its election. But within a week, the story had spread nationwide.

The government offered a reward of 42 million won ($30,880) to whoever found the boys and mobilized some 320,000 police and military personnel to search more than 140,000 locations. About 22 million flyers were distributed across the country, and the children's’ faces were printed on cigarette packs, postcards and video tapes.

The search, however, only led to false tips and misinformation.

The fathers received as many as 200 to 300 tips from shamans alone throughout the search. One claimed the children might be in Naju, South Jeolla; the parents followed her directions to the city and sifted through a garbage truck there but did not find a trace of the boys.

Korean National Police Agency Commissioner General Min Gap-ryong visits the site Mount Waryong in Daegu where the remains of the Frog Boys were found on Sept. 20, 2019. [YONHAP]

In 1996, a KAIST professor who had studied criminal psychology in the United States alleged that the boys were all buried beneath the home of Kim Jong-sik. Police excavated the property but found no evidence. The professor, identified only by his surname, Kim, was later fined for defamation.

An unwanted discovery and its chaotic aftermath

On Sept. 26, 2002, well into the 11th year of the search for the Frog Boys, a hiker who was searching for acorns came across a heap of bones, shoes and clothing on the eastern side of Mount Waryong, right where witnesses believed the five had been heading when they'd vanished. After a DNA investigation, they were identified as the remains of the Frog Boys. They'd been hidden just outside the area police had thoroughly searched.

The parents of the Frog Boys view belongings recovered from Mount Waryong in an undated photo taken at Kyungpook National University in Daegu. [JOONGANG ILBO]

Police concluded that the boys had died from hypothermia; rain had fallen the afternoon they disappeared, with temperatures ranging from a midday high of 12.3 degrees Celsius (54.1 degrees Fahrenheit) to a morning low of 3.3 degrees.

But forensic experts thought otherwise. The team from Kyungpook National University in charge of the forensic investigation determined that the boys had been murdered. They cited intentional trauma to at least three skulls. Woo Cheol-won’s skull, for instance, displayed square-shaped damage on each side, injuries the team said could not have resulted from natural decomposition. The trauma appeared to have been inflicted at the time of death.

The experts also pointed to the condition of the remains. The bones were neatly buried, rather than scattered or damaged, which suggested immediate burial after death; animal interference would otherwise have been expected.

Bullet casings and bullets were also discovered among the, remains, though the nearby military unit said no training had been scheduled that day, as it was a public holiday due to the election.

“It’s impossible to determine the cause of death from bones buried for ten years,” said forensic medicine Prof. Na Joo-young of Pusan National University during an interview with SBS’s investigative program Unanswered Questions on May 14, 2011.

“But it’s also rash to conclude the cause of the death while ignoring the visible damage.”

Police temporarily classified the deaths of the Frog Boys as a homicide, but no suspects were identified, and the statute of limitations expired on March 25, 2006 — leaving the truth behind their fate a mystery.

Forensic investigators from Kyungpook National University share their findings after examining the remains of the Frog Boys on Sept. 28, 2002. [JOONGANG ILBO]

The decades-old mystery resurfaced in 2022 when an anonymous user posted the shocking claim on Nate Pann, a popular online community, that they knew the truth of the Frog Boys' death.

“I know the weapon used in the Frog Boys case,” the post, uploaded on June 1, 2022, was titled.

The writer claimed the murder weapons were Vernier calipers, a measuring tool used for circular objects. They alleged that the boys had encountered a group of high school students who were high from sniffing glue on the mountain who had murdered them to prevent them from reporting what they'd seen. A vocational high school was near the location of the remains.

Following the post, Daegu police said they had already received reports in 2002 suggesting the possible use of Vernier calipers when the remains were discovered. However, they said forensic investigators at the time had concluded the injuries to the skulls did not match such a tool. The possible lead became another dead end.

Students at Seongseo Elementary School in Daegu hold photos of the Frog Boys during a joint memorial service on March 26, 2004. [CHO MUN-GYU]

Five families at square one

The five bereaved families have long accused the police of mishandling the case, criticizing what they say was a sloppy and insufficient investigation during the critical early period of the boys’ disappearance. They've argued that police failed to properly investigate the nearby military base and ignored key witness testimony, including that of a fourth grader who claimed to have heard a “horrendous scream” from the mountain that day. They ended up suing the government in 2005, but the court ruled that there had been “no violations of the law” during the police investigation.

Still, those in mourning hold out hope that the truth will one day come to light. The abolition of the statute of limitations for first-degree murder in 2015 has kept the door open for investigations to resume if new evidence emerges.

Daegu police reopened the Frog Boys case in 2019, the same year serial killer Lee Choon-jae admitted to murdering 10 women and girls in Hwaseong, Gyeonggi, between 1986 and 1991.

The unresolved cases team at the Daegu Metropolitan Police Agency has been reinvestigating “from the starting point” since then, but no definitive evidence has yet emerged.

Woo Jong-u, father of Woo Cheol-won, reads a eulogy at the memorial service on Mount Waryong in Dalseo District, Daegu, on March 27, 2023. [NEWS1]

“I have nothing else left, but only the question of why they took our five kids,” said Jo's father during an interview with SBS's true crime show "Tails of Tales" (2020-) on Jan. 11, 2024.

The Frog Boys' funerals, long postponed due to the investigation, finally took place on March 26, 2004. The remains were cremated and scattered in the Nakdong River — except for the skulls, which their parents chose to keep in hopes that they could one day help bring the killer to justice.

BY CHO JUNG-WOO [[email protected]]