The 16-year-old girl, resident of Omnagar, was raped by Rakesh alias Chhotu, who belongs to same locality, on September 15 at his neighbour's house, a police official said.
The neighbour, identified as Angrejo Devi, had stood guard outside the house during the crime, the official said, adding she too has been booked in the case.
Rakesh later threatened the girl of dire consequences if she informed anyone about the incident.
Gogi, another man from the same locality, somehow got to know of the incident and blackmailed the girl over it and raped her, said investigating officer Kamlesh.