Satomi followed her friend to a nearby study room. Once there, the younger girl closed the curtains. Then, without warning, she used a box cutter to slash Satomi’s throat and continued to kick her in the head and torso, according to The Washington Post.
Covered in blood and still holding the weapon, the girl returned to the classroom where she reportedly told stunned classmates, “This is not my blood.” Moments later, a teacher discovered Satomi’s lifeless body lying face down on the study room floor. She was no longer breathing.
Satomi’s father, Kyoji Mitarai, recounted the horror to reporters at the time.
“When I arrived, Satomi was already lying there collapsed. I couldn’t believe what I was seeing. I can’t put in words what I’m feeling. I don’t understand it at all. I have no clue.”
The attacker, referred to publicly only as “Girl A” due to her age, quickly confessed, reportedly telling investigators, “I have done a bad thing.” She was immediately taken into custody, and the case shocked a nation already grappling with a disturbing rise in youth violence.
At the time, Japan was still reeling from several high-profile cases involving children committing deadly acts. In 1997, a 14-year-old boy in Kobe decapitated an 11-year-old and left his head at the school gate. In 2003, a 12-year-old pushed a 4-year-old off a rooftop in Nagasaki, resulting in the child’s death.
Girl A was said to be fascinated by violent content, including the controversial Japanese film Battle Royale, which depicts students forced to kill one another. Reports also indicated that she had been active in online chat forums and had allegedly been mocked by Satomi, who called her “overweight” and “prissy.”
According to police interviews cited by the BBC and Yomiuri Shimbun, the girl told investigators:
“She wrote something bad about my appearance several times online. I didn’t like that, so I called her to the study room and slashed her neck after getting her to sit in a chair.”
She had reportedly decided to carry out the killing four days earlier and chose the weapon after watching a violent drama on television.
“I saw that drama. I thought I’d do it that way,” she allegedly said, according to the Mainichi newspaper.
After Satomi’s death, the school was faced with a sensitive dilemma: whether to include photographs of both girls in the graduation handbook. After discussions with parents and a vote among students, the school decided to include Satomi’s photo, while leaving a blank page for Girl A, allowing each student to decide whether to add her image or not.
In a gesture of closure, the school also issued posthumous graduation certificates to both girls. Satomi’s was delivered to her grieving family. Girl A received hers while detained in a juvenile correctional facility, a move meant to support her eventual reintegration into society.
In September 2004, a family court sentenced Girl A to a state-run juvenile facility and ordered mandatory counseling as part of her rehabilitation. She was expected to remain under state supervision for several years, with the aim of continuing her education and, eventually, returning to public life.
The case remains one of the most haunting examples of youth violence in Japan, prompting national debate on juvenile crime, online bullying, and mental health support for children.