The students took out a procession from R K College premises demanding arrest of the culprits and CBI probe into the mysterious disappearance of Prashant Kumar (17) from Indian Public School last month, police said.
The protesters turned violent as they reached near civil court premises and started pelting stones at a prisoners' van, SP P Saurabh Kumar said.
They let out the prisoners before setting it on fire.
The students later marched towards the district collectorate and nearby government hospital where they tore down hoardings and banners of the government, he said.
Upon reaching town police station, the students pelted stones at the police station premises before setting on fire dozens of vehicles parked there, Kumar said.
One person died and at least 12 others, including Deputy Superintendent of Police (Headquarters) S Khalifa and three constables, sustained injuries in heavy stone pelting by the protesters, the SP said.
The injured were admitted to hospital.
To control the situation, police burst teargas shells and fired in the air, Kumar said.
Additional policemen with anti-riot vehicles were deployed in the town.
The students were demanding arrest of District Project Officer, Education, Jagpat Chaudhary, education department employee Narayan Jha and teacher Bechan Jha.
