An explosion ripped through a two-storey mud house of a Trinanmul Congress leader at Bhupatinagar in East Midnapore on Friday night, killing him, his cousin and another person, whose bodies were later found in nearby paddy fields.

Two men suffered serious injuries in the blast which, according to the BJP, occurred when crude bombs were being manufactured at the house.

The spot of the blast is 30km from Contai where Trinamul Congress national general secretary Abhishek Banerjee held a meeting on Saturday. The impact of the explosion was so powerful that the tinned roof of the two-storey mud house blew off.

Police found the three dead bodies in nearby paddy fields on Saturday morning and started a probe.

The deceased were Rajkumar Manna, 58, Trinamul booth-committee president at Naryabela village in Bhagabanpur Assembly constituency, his cousin Buddhadeb Manna, 46, and Trinamul worker Biswajit Gayen, 37.

“We are yet to find out the actual reason behind the explosion. The investigation has started,” said a senior police officer in East Midnapore.

A police source said around 11.15pm on Friday, the residents of Naryabela village had heard the explosion and found out that it had happened at the house of Rajkumar. Although a team from Bhupatinagar police station reached the spot late at night, no bodies were found then.

“The bodies were found at different places in nearby paddy fields. The bodies were sent to Contai hospital for postmortem,” said a police officer.

The BJP demanded a probe by the NIA, alleging that the explosion had taken place when Trinamul workers were making crude bombs to attack BJP supporters.

“The explosion happened while Trinamul men were making crude bombs at the house of their leader Rajkumar.... There was an attempt to hide the bodies of those killed in the explosion. We suspect more people died in the incident,” Baghabanpur BJP MLA Rabindranath Maiti.

Suvendu Adhikari, the leader of the Opposition, also demanded an NIA probe into the explosion and wrote to Union home minister Amit Shah for the same.

Trinamul, however, claimed that the explosion was the handiwork of the BJP. “It was the BJP that was behind the explosion. The bombs were kept to attack the rally in Contai. We demand a thorough probe,” said Trinamul spokesperson Kunal Ghosh.