A teenager starved to death months after being detained. Her mom’s taking police to court

By Hanako Montgomery, Junko Ogura, Chris Lau, CNN

Tokyo (CNN) — In the 18 days Runa spent in a police cell in Japan, she wrote about how much she yearned to come home.

The teenager missed her mother’s cooking, her hugs, and their small, ordinary rituals of life together – reading, shopping, and singing.

“Please, I beg you. I want to see my mom,” she scribbled in a notepad given to her during her detention, seen by CNN.

Runa’s incarceration – and death months after her release – is now the subject of a lawsuit brought by her mother against Hyogo Prefectural Police alleging unlawful arrest and detention. Proceedings opened this week in a case that’s shone a spotlight on Japan’s treatment of juvenile suspects.

“I feel so sorry for Runa that I failed to protect her myself,” Runa’s mother Yoko told CNN through tears and staggered breaths, using an alias for privacy reasons. CNN has withheld Runa’s full name at her mother’s request, for the same reason.

Yoko said Japanese police held the 16-year-old for 18 days last year on suspicion of an assault at the care home she runs for people with special needs. Police declined to comment or share details of the complaint, and CNN has been unable to independently verify the allegations.

Yoko said her daughter simply tried to prevent an agitated resident from biting others by putting her hand around the person’s chin. Runa denied the allegation and was never charged.

During her incarceration, Runa stopped eating and after her release, she was diagnosed with post-traumatic stress disorder.

Her weight continued to drop, and she died five months later, weighing about 20 kilograms — the average weight of a 6-year-old girl.

Her single mother is seeking 109 million yen ($700,000) in damages, alleging unlawful arrest and detention, which she said led to Runa’s death.

“I want the police and prosecutors to reflect on their duty to care for people and protect citizens, and to tell the truth in court,” she said.

The rules around juveniles in custody

Japan has a reputation for “hostage justice,” a term referring to the detention of suspects without charge for far longer than the law in other countries would allow, often for days, if not weeks.

But the country also has strict rules governing how minors should be treated during a criminal investigation. Under Japan’s Juvenile Law, minors should only be incarcerated when it’s “unavoidable.”

However, defense attorney Megumi Wada said the meaning of “unavoidable” had never been clearly defined, and was open to interpretation by authorities.

More than 6,000 suspects under the age of 20 were detained in 2024 – and of those, 4,000 were held for more than 15 days, according to government statistics.

The decision to deny Runa access to her mother, and detain her for more than a fortnight, has baffled lawyers, raising questions about whether measures to protect minors in custody are working.

Mikio Uehara, a public prosecutor turned defense attorney, said Runa’s death was “extremely tragic.” “I have strong doubts as to whether detention was truly necessary,” he added.

When asked for the reasons behind Runa’s detention, the Hyogo Prefectural Police said it would not “comment on the details of individual cases.”

“This matter is currently the subject of a pending lawsuit for state compensation, and the prefecture’s position will be made clear in court,” a spokesperson said.

Japan’s Ministry of Justice has repeatedly rejected allegations of “hostage justice,” saying that it gives due consideration to the rights of people accused of wrongdoing.

A life upended

The family runs a care home in Hyogo prefecture, located in the northwest of Osaka, Japan’s second-biggest city.

Growing up around people who needed extra care, Runa was a “cheerful girl” who aspired to take over the family care home one day, her mother said.

“Although her life was short, only 16 years, she lived every single day without ever forgetting compassion and care for others,” said Yoko.

But the arrest of Runa on June 17 last year – four months after the alleged assault – upended everything. Police detained Runa at the care home and took her away before her mother, who had rushed back to the facility upon hearing the news, had a chance to see her, Yoko recalled.

For the next 18 days, Yoko was barred from visiting Runa due to a ban sought by the prosecutors – and granted by a court – over concerns that she, as the owner of the facility, could tamper with the evidence.

Through Runa’s lawyer, she began to learn that her daughter wasn’t eating properly. But she was never informed of the full extent as authorities rejected her requests for Runa’s meal records, she said.

The night before her release, the teenager collapsed and was rushed to the hospital, she said.

The next morning, Yoko was shocked by what she saw.

“She had become skin and bones and came out screaming and crying,” Yoko recalled.

“Her stride was so feeble it took everything she had just to walk 10 meters, not even 5 meters,” she said, adding that they had to carry her to the car.

An anxious child

Apart from her scribbled notes, scant details are available about Runa’s experience in detention, according to her lawyer Yoshihiro Mukai.

“When we met her, she was overwhelmed with anxiety, repeatedly asking what would become of her,” Mukai told CNN, of their meetings during her detention.

Japan has facilities – known as Shonen Kanbetsu Sho – dedicated to temporarily housing juvenile suspects. But defense lawyer Wada said they were seldom used when the detention was shorter than two weeks, leaving minors to face similar conditions to their adult counterparts.

It’s not clear why Runa wasn’t moved to a juvenile facility after the first two weeks in custody.

Wada also raised another peculiarity in Runa’s case. “I have never seen cases where the parents couldn’t see the suspects,” she said.

A separate police guideline requires investigators to do their best to accommodate juvenile suspects’ requests for the company of an appropriate adult, such as a parent, even during interrogation. But the right is not absolute, said Tomonobu Ishida, a law professor at Meiji University in Tokyo.

“They are essentially internal rules or administrative guidelines for the police, and therefore do not have the legally binding force,” Ishida said.

“However, even assuming that there was a genuine risk of destruction of evidence, I personally have some difficulty seeing how such a relatively long period of detention could be considered proportionate, given the relatively minor nature of the alleged conduct and the fact that she was a juvenile,” Ishida said.

Calls for change

After Runa’s release early last July, she became suspicious of adults, including the doctors and nurses who came to treat her, Yoko said.

Yoko said they tried to feed her food that might revive her appetite – from ice cream to nuts – but “everything just passed right through her system.” Runa’s distrust in the system complicated rescue efforts as she refused to be taken to hospital.

Psychiatrist Mai Uchida said it’s crucial not to mistake teenagers for a “smaller version of adults,” saying their emotional and cognitive control is still developing, which causes them to experience and process stress very differently. Runa’s death was attributed to malnutrition due to an eating disorder.

Loss of appetite is common following traumatic events, she said, adding that it cannot be reversed simply by encouraging the person to eat more.

“It is certainly possible that PTSD could cause functional difficulties in the (gastrointestinal) system, as well as making a difference in the appetite and causing significant amount of weight loss and that would connect to death,” said Uchida, an associate psychiatry professor at Harvard Medical School.

Human rights groups have long warned of the undue stress suspects in Japan are subject to during detention, ranging from aggressive questioning tactics to the lack of access to lawyers. Some legal experts said prolonged detention occurs far too often, regardless of the suspect’s age.

In 2024, about 65% of the 85,040 adults detained in Japan spent more than 15 days in police custody, according to government statistics.

“I completely fail to understand how such a practice is allowed to pass, and this broader reality urgently needs reform as well,” said lawyer Uehara.

Yoko hopes her bid to seek justice on her daughter’s behalf could play a role in driving change.

“Winning this lawsuit would mean that, even if Runa is no longer physically here, it will serve as proof that she lived and left a legacy behind to reform this justice system.”

The-CNN-Wire
™ & © 2026 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.

If you or someone you know is struggling with an eating disorder, help is available. In the United States, call the National Alliance for Eating Disorders’ helpline for free on 1-866-662-1235. A list of international directories is provided on eatingdisorderhope.com.