Kolkata, Sep 3 (IANS): A Bharatiya Janata Party (BJP) worker was allegedly beaten to death inside a police lock-up in West Bengal's North Dinajpur district.

The incident took place late on Wednesday night when the police arrested Anup Roy, a resident of Nandan village. He was picked up in connection with a robbery case.

"We picked him up in connection with a robbery case that took place on August 28. After interrogating the robbery gang, we came to know about Anup. After we took him to the police station, he suddenly fell ill in the police lock-up. We took him to the nearest hospital where he died," said North Dinajpur police superintendent Sumit Kumar.

The family members of the deceased, however, claimed that the officers at the Raiganj police station had left the body of Roy at the Baroborua area quite late at night. The post-mortem was also conducted in a hurried manner in the night.

Reacting angrily to the incident, the district BJP unit called for a protest outside the Raiganj police station on Friday. It was also alleged by the BJP that Roy was beaten to death by the police during interrogation while in custody.

Roy was taken to the Raiganj hospital on Wednesday night where he was declared brought dead.

The police, however, claimed that the BJP worker had suffered a heart attack in the lock-up and hence was taken to the hospital for necessary treatment.

"It was completely illegal. He was picked by the police without any valid basis. No one in his Roy's family was informed about the arrest. We have protested against the police atrocities and demanded a fresh post-mortem," said BJP state president Dilip Ghosh.

Local sources said that Roy was a Communist Party of India-Marxist (CPI-M) supporter before he joined the BJP about seven months ago.