The Tokyo Metropolitan Board of Education has set up a special investigative committee to look into whether a 16-year-old boy who killed himself in September had been bullied.

The student of a school run by the Tokyo Metropolitan Government jumped off the platform of JR Chuo Line's Otsuki Station in the city of Otsuki, Yamanashi Prefecture, on the evening of Sept. 27.

The teen was struck by a train and killed. His name has not been released, but his family have expressed their feelings of devastation to reporters.

"We are left wondering why a boy with a clear dream for his future had to die. I would like to know what actually happened in school," the boy's mother said Monday.

The family has called on the school to investigate whether the student was being bullied, as messages left on his Twitter and Line accounts suggest he was in some kind of trouble.

In mid-November, the school conducted a survey of its students. The metropolitan government judged that, based on reports from the school, further investigation was necessary.

Separately, school officials say they have interviewed the boy's classmates and other students who interacted with him during extracurricular activities but they have been unable to detect signs of bullying. The family has meanwhile requested the thorough investigation of all the facts — not only the circumstances that led to his death but also the way the school handled the matter.

"We will continue the investigation carefully so as to meet the request," said Takashi Sakata, a professor at Japan Women's University who heads the investigative committee.