Ram Sajjan Satva, a resident of Barhara village, died on Saturday after he was allegedly beaten up by policemen following which a crowd gathered outside the police station and pelted stones, injuring several police personnel, District Magistrate Birendra Prasad Yadav said.
"The protesters also entered the police station and torched a portion of it," Mr Yadav said.
Several vehicles parked outside the police station, furniture and some documents were set afire by the angry mob, the DM said, adding fire tenders were pressed into service to bring the situation under control.
SDO Navdeep Shukla and SDPO Sanjay Kumar along with a team have gone to the village to control the situation, he said. Meanwhile, a medical report has said that Satva died of severe head injuries.
Satva's kin has alleged that he was killed in police custody. However, the police have claimed that the victim died after he jumped off the vehicle when he was taken to a government hospital for medical examination.
An investigation into the matter has been launched, the magistrate said.