SP, Police Control, Uttam Kumar Bhowmick said Kameswar Sinha (59), who participated in a procession to support the 12-hour bandh called by the Congress in the state, suddenly fell down and was immediately taken to Damcherra rural hospital where attending doctors declared him dead on arrival.
The 12-hour bandh, which was called to protest against police atrocities, evoked mixed response.
As many as 1,600 picketers were arrested from different parts of the state and were later on released, IG, Police Control, Nepal Das said.
No untoward incident was reported from anywhere, he added.
The bandh was called against clashes between Congress activists and the police during a civil disobedience programme launched by the party to protest rampant corruption by cadres of the ruling CPI(M). The party also demanded the resignation of Chief Minister Manik Sarkar.