On Sunday morning, as the protests grew bigger, a thousand people joined in.
At least 52 police personnel were injured as violent protesters pelted stones at the police at Sakthi Matric Higher Secondary School in Tamil Nadu's Kallakurichi district after a teenaged girl killed herself on Tuesday.
The area turned into a war zone as school buses and police vehicles were torched by protesters. A group of youngsters also rammed a tractor into some buses.
Police used force to bring the situation under control. Reinforcements were also sent from Chennai.
In a note, the girl, a student of class XII, had alleged torture by her teachers. Peaceful protests had been going on outside the school, with demonstrators demanding action against the teachers. On Sunday morning, the protests grew bigger and more violent, with more than a thousand people joining in.
Chief Minister M K Stalin expressed his sadness about the situation. He tweeted: "At the end of the police investigation the guilty will certainly be punished. I've directed the Director General of Police (DGP) and Home Secretary to visit Kallakurichi. The public should keep calm and have faith in the government".
The police have invoked Section 144 of the Code of Criminal Procedure in Kallakurichi and Chinna Salem Taluks.
Tamil Nadu's DGP Sylendra Babu said that the case has been transferred to the Crime Investigation Department (CID) of the police. "The principal, secretary and correspondent of the school have been arrested. Separately, 70 protesters have been arrested for the riots. The situation is under control," Mr Babu told NDTV.
Pattali Makkal Katchi (PMK) chief Anbumani Ramadoss blamed the police for the law and order situation in the area. In a tweet, he said: "Police's inaction, instead of resolving the issue by taking action against the guilty, is condemnable." He added: "If the school was guilty, they should have taken prompt action. If they weren't guilty, they should have explained it to the parents."
The girl's father has moved the Madras High Court seeking another post-mortem and a CB-CID (Crime Branch-Crime Investigation Department) probe. The District Collector has advised a deputy superintendent of police (DSP) to be present in the court tomorrow.