A teacher accused of stabbing an 8-year-old student to death at an elementary school in the central city of Daejeon said she was ?annoyed? after being excluded from a class, police said.

?I got annoyed just three days after returning to work,? she was quoted as telling the police, after accusing another person who was not identified of stopping her from teaching a class.

The female teacher in her 40s gave the statement to police after admitting she stabbed the girl on the second floor of the school when she was arrested on Tuesday.

The girl was later pronounced dead at a hospital due to excessive bleeding.

Police said the suspect was found to have received treatment for depression since 2018 and thought of killing herself while on a six-month sick leave that began in early December.

She returned from her leave early, however, and on the day of the attack, purchased a weapon before returning to the school in search of a target.

The teacher told police she waited for children to file out of an after-school class with the intent of dying together with a child.

?I told the last child leaving that I would give her a book and took her with me to the audiovisual room where I strangled and stabbed her,? she was quoted as telling police.

The suspect also stabbed herself and is currently recovering at a hospital.

She was found to have showed signs of aggression earlier as well, including last Thursday, when she twisted the arm of another teacher on Feb. 6, for asking if anything was wrong.

The two were separated by other faculty members, but no reports were filed with the police at the time.

Police said they have asked the National Forensic Service to conduct an autopsy of the child?s body to help determine the exact cause of death. (Yonhap/NAN)

Update news