Drugs

The dictator were abusing the student exploiting them of their soul making sure each of their strength were being used up for the dictator bank balance. The dictator also made sure of the student of their uses of drugs like cocaine or heroine since for the dictator, banning the students of using the drugs would just be inhumane for the students to ease their pains. The dictator would also supplies the student with the drugs he could get from some of the biggest drug dealers. Of course, their parents won't be informed of their children used of drugs. If the parents knew that their children were using drugs, the dictator might be brought down.

The dictator did a negotiation with the representative of the student council to made sure that anyone trying to spoke out the truth that was happening inside the school to just stay there. Any scandal that the student trying to made against the dictator, the students would be directly shot by the guard or the teachers.

Of course for the dictator, a few students dead inside the school doesn't matter as long as words of them dead would not went out to the world. And then, the only problem was to trick the parents into thinking their children was still alive and doing well in the school. After tricking them, the dictator would be sending a hitman to quietly kill their parents before burying them alongside their houses too. Their houses would be destroyed and buried alongside their bodies at night in the dark so nobody would found out about it.

This method of both killing their families and secretly burying the massive scandal the dictator had was a really good method according to the dictator since not only it would be the best way to save money but avoid the dictator of having any type of bad scandal that would harm his power as the leader of his country. The dictator knew that to made sure the students didn't started rioting in the school, he needed to be killing those problematic students before they could even spoke a single word. Each classes in the school would had a student that the dictator would be corrupting with money so that they could informed the dictator of potential resistance.