A BJP supporter in North Dinajpur died on Wednesday evening, a few hours after his arrest in connection with a crime, prompting district party leaders accuse the police of killing him in custody and demand a CBI inquiry.

The bereaved family of Anup Roy, 23, seconded the party’s allegation and demands.

Police, in turn, said Anup fell ill. The report of a post-mortem done on Wednesday night, out on Thursday, stated cerebral haemorrhage as the cause of death. BJP leaders demanded a second post-mortem.

Sources said on Wednesday around 1pm, a team from Raiganj police station went to Nandangram village of Itahar block. There, they arrested Anup, a former CPI supporter who defected to BJP around six months ago, in connection with a recent snatching case.

Some youths on bikes had held two traders at gunpoint and looted Rs 1 lakh on NH34 in Ghughudanga More of Raiganj on August 28. Four youths who were arrested reportedly named Anup as mastermind during their interrogation. Anup was accused of planning the crime, arranging the bikes and firearms and handing over a share of the booty to these youths.

“We brought him (Anup) for interrogation but after some time he suddenly fell ill and was rushed to Raiganj Government Medical College & Hospital. There, he died late in the evening. Nevertheless, an inquiry into the death has been ordered,” said Sumit Kumar, North Dinajpur SP.

BJP leaders were not ready to buy the post-mortem report.

“He has been murdered in police custody, and to conceal it, the post-mortem was done at night. We want the post mortem to be done before a magistrate during daytime and a CBI investigation into the case,” said Biswajit Lahiri, North Dinajpur district BJP president.

Gita, Anup’s mother, said: “We suspect my son has been brutally tortured and that is why he has died. Also, the police tried to implicate him falsely in a case. We want the CBI to investigate.”

On Thursday evening, some BJP leaders blocked Raiganj’s MG Road to raise the demands.