About 300 men have been detained for their involvement in vandalising the school, police said.
Two teachers of a school were detained on Monday in connection with the death of a girl student, police said.
Also, about 300 men have been detained and are being questioned for their involvement in violent acts and for vandalising the school on July 17, they said.
On Sunday, 70 people were arrested for violence and 2 men and a woman holding senior positions in the school management were held in connection with the girl's death.
The two teachers teaching Maths and Chemistry face allegations from the dead girl's family and it includes torturing their child over her studies.
A 17-year-old girl, studying Class 12 in a private residential school in Chinnasalem's Kaniyamoor area, was found dead on July 13 on the hostel premises. Kallakurichi is about 260 km from Chennai and is near Villupuram in northern Tamil Nadu.
Reportedly, a postmortem report indicated that she had sustained injuries before her death. Police registered a case and initiated probe.
Her parents, relatives and people belonging to her village Periyanasalur, off Veppur in Cuddalore district, have been staging non-stop protest raising suspicions in connection with the teenager's death and seeking justice.
The protests were being held in both Kallakurichi and Cuddalore Districts.
Blaming the school authorities and seeking action against them they held a protest here on July 16 for the fourth successive day.
Their demands that have the support of a political outfit and the youth wing of a Left party include probe by an independent investigating agency and arrest of those responsible for the girl's death.