The incident occurred yesterday when the woman was going to answer nature's call, they said.
Engineering student R Mohan, was a resident of the same locality where the victim (18) lived, took her into his house yesterday afternoon and allegedly sexually violated her, inspector at Vanasthalipuram police station, P Gopala Krishna M, said based on a complaint lodged by the woman last night.
A case has been booked in this connection and a hunt has been launched to nab the student, who is at large, the officer, said, adding that the woman was sent for medical examination.