A XNUMX-year-old student from an elementary school in the Brazilian city of Sao Paulo attacked his teachers with a knife today, killing one and injuring three, and injuring two other students, officials said.

The five injured were hospitalized and are in stable condition, and the suspected attacker was detained by the military police and is now under investigation.

The murdered teacher was 71 years old. Last week, she tried to resolve the conflict between the attacker and a student, when they were fighting.

"That boy called the other boy a monkey and a rat, the boy didn't like that, so they started fighting," said a student who was in the same class as the attacker.

According to him, the attacker did not like how the teacher intervened, so he said that he would do something about it.

Today, the attacker entered the class wearing a mask with a skull motif over his head, then stabbed the teacher from behind - in the head and in the back, said his classmate and added that then everyone started to run away.