A South Korean court sentenced a teacher to life in prison for the murder of a seven-year-old student at an elementary school in Daejeon earlier this year.

The Daejeon District Court said 48-year-old teacher Myung Jae-wan who had displayed emotional instability and workplace maladjustment, deliberately targeted a defenseless victim to vent her anger.

According to the court's ruling, Myung lured a first-grader into a classroom on the pretext that she would give her a book and then fatally stabbed her. The court called the crime “unprecedentedly brutal," saying it had been committed in the place that should have been safest for children.

Despite the defendant's signs of psychological distress, the court found no grounds for diminished responsibility, citing evidence of premeditation and attempts to conceal the crime.

The ruling stated that the teacher had betrayed her duty to protect students and that “society must be permanently protected from the defendant’s danger.”

Myung, who was dismissed from her position in April, was also found guilty of assaulting a colleague and damaging school property days before the murder.