Police sub-inspector S B Kamble of the Nallasopara police station told PTI that the girl whoe parents deserted her after they separated, had been living with one of her aunts in Nallasopara.
Two years ago, one of the accused took her to his room and allegedly raped her, according to the complaint.
However, the girl never realised what had been done to her until she attended a sex education class at school, after which she narrated the incident to her teacher, who filed a police complaint, the police official said.
One of the accused identified as Dileep Shingare (31) has been arrested, while the other one named Mahesh is still at large, the police official said.
The police officer said that if it was not for sex education lessons, the girl would have never got any opportunity to complain.