The teacher who fatally stabbed an elementary school student in the central city of Daejeon on Monday told the police she did so after feeling irritated because she was excluded from teaching duties.

According to the head of the Daejeon Seobu Police Station on Tuesday, the teacher in her 40s said she felt irritated just three days after returning to work after a medical leave because the vice principal restricted her from teaching.

The teacher, who had been treated for depression since 2018, began a six-month medical leave on December 9, but cut her leave short and returned to school late last year.

Having purchased the weapon Monday afternoon, the teacher said she waited to kill one of the students leaving the after-school child care program before killing herself.

She said the victim was the last student to leave the classroom and she enticed the girl to enter an empty audiovisual room by offering her a book, then choked and stabbed her.

The police, however, said further investigation is required to determine whether the offense was premeditated.