The accused has been identified as Nimma Somiraju (19) and a woman security guard of a girl's hostel allegedly helped him, in the incident that took place on December 19 last year.
The matter only came to light today after her family members lodged a complaint in this regard.
The former woman security guard of the hostel, K Simhachalam, took three girls from there, including the student of class X, to Kotavuratla mandal in district in an autorickshaw, police said.
The driver of the rickshaw later raped the girl at a lodge, while Simhachalam and the two other girls were outside.
Both the accused threatened the girls with dire consequences if they informed anyone of the crime and dropped them back at the hostel at Nathavaram, police added.
The girl finally told her parents about the incident today, who, along with their relatives and members of some NGOs, held demonstrations outside the hostel before lodging the police complaint.
Nathavaram police have registered a case and a search is on to nab the accused.