A Japanese mother has filed a 109 million yen ($700,000) lawsuit against police, alleging that the detention of her 16-year-old daughter triggered a traumatic decline that ultimately led to the teenager’s death from malnutrition.
The case, which opened in court this week, has renewed scrutiny of Japan’s treatment of juvenile suspects and the restrictions placed on detainees’ contact with their families.
The teenager, identified only as Runa to protect her privacy, was arrested on June 17, 2025, over an alleged assault involving a resident at a care facility operated by her mother in Hyogo Prefecture. Her mother maintained that the girl had only intervened to stop an agitated resident from biting other people.
Runa denied the allegation and was never formally charged. However, she spent 18 days in custody after prosecutors obtained a court-approved restriction preventing her mother from visiting her over concerns that evidence could be tampered with.
According to her mother, Yoko, the teenager struggled to eat while detained and repeatedly wrote notes pleading to see her family. In one message, she expressed anxiety over her inability to eat despite insisting that she had done nothing wrong.
Her mother said she was not given complete information about her daughter’s condition or access to her meal records, despite concerns raised through the teenager’s lawyer.
The situation reportedly deteriorated shortly before Runa’s release, when she collapsed and was taken to hospital. Yoko recalled that her daughter emerged from detention severely weakened and unable to walk even a short distance without considerable difficulty.
Following her release in early July 2025, Runa was diagnosed with post-traumatic stress disorder (PTSD). Her mother said the teenager became distrustful of adults, including healthcare workers, and resisted attempts to take her for medical treatment.
Efforts to restore her appetite through foods such as ice cream and nuts proved unsuccessful. Runa continued losing weight and died five months after her release, weighing approximately 20 kilogrammes. Her death was attributed to malnutrition associated with an eating disorder.
Psychiatrist Mai Uchida, an associate professor at Harvard Medical School, explained that traumatic experiences can affect appetite and gastrointestinal functioning, potentially contributing to severe weight loss. She also stressed that psychological trauma in adolescents requires specialised attention because their emotional and cognitive development differs from that of adults.
Runa’s case has prompted legal experts to question why a minor accused of relatively minor misconduct was detained for more than two weeks and prevented from seeing her mother.
Japanese law provides that minors should be detained only when considered unavoidable. However, defence lawyer Megumi Wada said the absence of a clear definition of that requirement leaves considerable room for interpretation by authorities.
Government figures cited in the report indicate that more than 6,000 suspects under the age of 20 were detained in Japan in 2024, with approximately 4,000 held for more than 15 days. The figures have added to concerns about the application of prolonged detention to young suspects.
Japan has also faced longstanding criticism over its criminal justice practices, commonly described by critics as “hostage justice,” referring to the extended detention of suspects before formal charges. Authorities have rejected allegations that the system disregards the rights of accused persons.
Hyogo Prefectural Police declined to discuss the specifics of Runa’s case, saying the matter was before the court and that the prefecture would present its position during the proceedings.
For Yoko, the lawsuit is an attempt to secure accountability for her daughter and potentially prevent similar cases. She said a favourable outcome would help preserve Runa’s legacy by encouraging reforms to the justice system.
The proceedings are expected to focus on the legality and necessity of the teenager’s detention, the restrictions on family contact and the extent to which the authorities could be held responsible for the events that followed.
