The girls, who were aged between 4 and 6 years old, complained of pain to their mothers after returning from school yesterday.
Angry parents beat up the accused inside the school premises on Friday while others protested outside the school.
“The three students, who are kids, complained about pain in their private parts, to their mothers last evening, after returning from school,” one of the parents said.
When they were taken to the doctor, he confirmed they had been sexually assaulted.
Dibyendu Sarkar, the accused, was dragged to the headmistress’ room and beaten black and blue up by the angry parents.
“We will not spare the man. He has touched the little girls inappropriately and sexually assaulted them,” one of the parents, who was enraged at the incident, said while others continued to beat the accused non-teaching staff.
The headmistress, on seeing that the situation was going out of hand, called the nearby Baguihati police station. Police arrived soon and based on the complaints by the parents, they arrested Dibyendu Sarkar on Friday morning.
It is learnt that there were no CCTV cameras inside the school, the headmistress has admitted.
The headmistress has also ordered a departmental enquiry into the incident, following the complaints filed by the parents