Photo/Illutration After their 12-year-old daughter took her own life, the girl's mother, left, and father call for a review of anti-bullying measures at schools at a news conference on Sept. 13. (Hiroyuki Maegawa)

A 12-year-old elementary school girl in Tokyo took her own life in November after being bullied by her classmates through the chat function on tablet computers distributed by her school, according to her parents.

The girl's parents and their lawyer held a news conference at the education ministry building on Sept. 13, where they disclosed details about the incident. They called on the government to review its anti-bullying measures and ensure that these types of devices cannot be used to bully other students.

“She was an innocent and cheerful child,” the girl’s mother said at the news conference. “I didn’t know she had been bullied until she killed herself.”

The girl was a sixth-grader at an elementary school run by Tokyo’s Machida city, and she had left notes that said her classmates bullied her.

Her classmates exchanged disparaging messages about her and called her “annoying” and “disgusting” through the chat function on tablet devices the school distributes to each student to use as a study tool, according to the girl’s parents.

A notebook titled “How to kill her” was also discovered and has been confiscated by the school.

The education ministry has encouraged elementary and junior high schools to provide a personal computer or tablet device to every student since April as part of an initiative aimed at promoting digitization in education.

But the girl's parents said the tablet devices became a hotbed for bullying and are urging the government to conduct a policy review to ensure other students are not similarly bullied.

The parents said they learned from their daughter's friends from the same class and from other parents that hurtful messages about her were sent over the devices through the chat function. The girl had named some of her classmates and described how she was bullied in notes she left behind, according to her parents and their lawyer.

The girl’s school had learned about “problems” between students last September and had kept tabs on them since then, according to the city’s board of education.

The board said it designated the case as “serious” one under the law to promote measures to prevent bullying in February. It began investigating after it set up a committee on anti-bullying measures in March.