The brothers were lodged in the Borstel School at nearby Pollachi, from where they were brought for carrying out various tests at the Government Hospital here, police said.
Both were taken back and lodged at the school, after the tests, they said.
The twins were arrested a couple of days ago following a complaint lodged by the girl that she was raped by them after being given sedative-laced soft drinks at their house in Thudiyalur on the outskirts.