Rakesh and some of his associates allegedly abducted the girl while she had gone to attend to nature's call on Tuesday night and took her to MLA Jagram Paswan's house.
The MLA was not present in the premises at the time of the incident.
She was locked in a room for 21 hours and allegedly gang-raped,
police said, adding that the girl was later dropped at a secluded place on Wednesday night using the MLA's vehicle.
On reaching her house she told her family about the incident leading to a strong protest by them and their neighbours who gathered at the MLA's house.
A case has been lodged and further investigations are on to identify the rest of the accused, police said.