The fight took place late on Thursday, the judicial authorities confirmed. A pupil who had been suspended, approached teaching staff to get some explanations. He was accompanied by his brother and a third youth.
During the conversation, the teacher's smartphone was stolen. This led to a new discussion, which eventually triggered a fight. Four teachers sustained injuries and were taken to hospital, with three of them being declared unfit to work on Friday.
The pupil's brother, who is no longer a minor, was arrested. The pupil, a minor, was taken to the Dendermonde youth magistrate. The third assailant has not been identified yet.