The deceased, identified as Shilpa Agarwal, used to operate a 'sahayak kendra' of a nationalised bank from her house at Mejia in Bankura district, the police said.
The arrested man, Rajiv Kumar, was the manager of the same branch, the police said.
The victim had told her family that she was going to visit her aunt's house at Asansol in West Burdwan district on Friday.
She was missing since Saturday and her family had lodged a complaint with the police.
Her family alleged that Kumar had committed the crime as Ms Agarwal had been demanding that he return the Rs 1 lakh which he had taken from her.
Police said investigations are on.
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