A warning for the teachers. Song, the former principal in South Korea, in fact already did not remember again that he had punished his pupil who was named Kim because of cheating during the exam more than in the last 20 years.

Song at that point then punished by striking Kim several times although the pupil denied he cheated during the exam in 1987 that. South Korean police in Seoul, on Monday (10/11), said, Kim that currently is 37 years old on Saturday stabbed Song that was 58 years old until being killed after the former principal refused to apologise.

Police kept Kim because evidently since last January, Kim urgent Song in order to apologise because has wrong punished himself on charges of cheating that never the implementation.

"He claimed really was angry with Song that, according to him, struck him more than 100 times," said police, quoted Kim. Since last January he urgent Song in order to apologise, but the teacher refused to apologise.

Kim then telephoned, sent the electronics letter, and came to the house Song to urge him to apologise. "I did not cheat. Apologise. I will not leave you alone", said Kim's message. Police currently interrogate Kim's mental health.