North district superintendent of police Manik Das said the trouble began four days ago when an inmate of Narsingpara camp in Kanchanpur sub-division was caught catching fish illegally from the pond of a person at a nearby village.
The 32-year-old man was beaten up by the pond's owner and fellow villagers. He was admitted to the Kanchanpur hospital with injuries and was released from there last Friday.
On hearing the news of his death, camp inmates attacked the pond owner's house and neighbours yesterday and torched 22 houses.
When the police reached there, the mob pelted stones injuring seven personnel. The situation has now been brought under control and a huge contingent of police have been deployed in the area, the SP said.
About 100 local residents have taken shelter in nearby safer places. Senior police officials were camping at the spot to avert any untoward situation, he added.