A Japanese schoolgirl who killed her classmate has offered an apology to her family and the victim's relatives as more details emerged of her motives.
Satomi Mitarai, 12, bled to death at her school on Tuesday
The girl reportedly told police she was annoyed by comments Satomi Mitarai made about her appearance during their exchanges in internet chatrooms.
This has prompted Japanese media to question the dangers of this form of communication.
Satomi Mitarai, 12, died on Tuesday after being slashed with a small knife.
"She wrote something bad about my appearance several times on the Net a few days before the incident. I didn't like that, so I called her (to a study room) and slashed her neck after getting her to sit on a chair," the Yomiuri Shimbun quoted Mitarai's killer, 11, as telling police sources.
Her lawyers said she had begun to question her actions, and had repeatedly expressed remorse.
"I wonder why I did it. If I thought and acted properly it wouldn't have happened. I would like to apologise," she was quoted as saying.
The Mainichi newspaper said she told investigators she had planned the murder four days earlier, and had been inspired to use a paper cutter after seeing the method used in a television drama.
"I saw that drama. I thought I'd do it that way", she was quoted as saying.
The Asahi Shimbun said classmates at Okubo Elementary School in Sasebo, southern Japan, had often seen her reading horror books, including Battle Royale, about schoolchildren killing each other.
Children are increasingly using online chatrooms to communicate, according to Yomiuri.
The newspaper quoted a professor in media studies as saying that this could lead to misunderstandings.
"Generally speaking, it's true that people communicating on the internet can bring people closer, but unlike other forms of communication, such as the phone, it's very hard to pick up the nuances and subtleties when talking online," Tasuo Inamasu, of Hosei University, told the paper.
But he said the internet alone could not be blamed for this crime.
"There must have been a lot that went before... I don't think we can blame computers for causing a murder," he told Reuters news agency.
There has been considerable hand-wringing in Japan over youth crime, ever since a shocking incident in 1997 in which a 14-year-old boy killed an 11-year-old and placed his severed head outside the gates of his school.
That prompted the country's parliament to lower the age of criminal responsibility from 16 to 14.
Last year a 12-year-old boy in Nagasaki was accused of murdering a four-year-old boy by pushing him off a roof.
The latest incident has shocked Japan's media.
"We must make children understand even more the basic importance of life," the Yomiuri said in an editorial on Wednesday.
Although Japan is still one of the safest developed nations in the world, youth crime has dramatically increased in recent years.
The number of children under 14 committing serious crimes in 2003 rose to 212, a 47% increase on the previous year.
Mitarai's killer, who is too young to be punished under the Penal Code, has been transferred to juvenile detention while her case goes before a family court, the Associated Press said.