The woman was kidnapped by four persons in a vehicle on June 26 and allegedly gangraped by them at Garapotha area, according to additional superintendent of police Bhaskar Mukherjee.
The accused left the victim in an unconscious state and fled after commiting the crim, he said.
The police started investigating the matter after the victim lodged an FIR with the Bonga police station yesterday, he said.
The woman was subsequently admitted to the Bonga hospital and later discharged.