An eleventh grader in Thanh Hoa Province stabbed his teacher Friday after the teacher told the boy's family about his truancy, local news website VnExpress said Sunday.
Le Ngoc Duc cut class and went down to the shool yard, only to intervene in a gymnastic session of teacher Doi Xuan Hai, said the school principle Le Quoc Tuan.
So Hai asked the school student supervisors to call Duc's parents and inform them of the case.
Several minutes after Duc's father came and cursed out Hai, Duc returned with Le Van Tu, a college student. Both young men were wielding knives.
Both have been arrested by the police.
Local doctors said that Hai lost a lot of blood and suffered a severed tendon in his left thigh.