The woman, who is in her thirties, had gone to the correctional home on August 13 but as she did not have the requisite documents could not meet him, police said.
She was allegedly offered help by the four, who took her to a room outside the prison premises and allegedly gangraped her. She was discovered lying unconscious in the room the next day by locals, who reported it to the police, they said.
The police rushed her to the local hospital. The woman in her statement to the police also alleged that she was raped after being made to drink liquor. Based on her statements, the four were later arrested and produced before the court, they said.
The juvenile was sent to the juvenile court, while the three others were sent to jail custody, they added.