A man identified as Md Munna took the 12 year-old girl to an isolated place at Jitwarpur village last night and allegedly raped her, Superintendent of Police (SP) Chandrika Prasad said.
The incident took place when the girl was returning to her house after visiting a fair in a nearby village
The accused was later arrested from the same village after the girl's family lodged an FIR in this connection, he said.
The girl has been admitted to a hospital for medical examination, the SP said.