Manoj Yadav, the accused, allegedly committed the crimes last night.
He was arrested today from Parahia village under Nadiganj police station, they said.
A pistol and 11 ammunition were seized from his possession, they added.
Raids were being carried out to nab Manoj's father Rameshwar Yadav, who, too has been named as an accused in the assault case.
The rape victim has been taken to a government hospital for medical test, they said.
Spotted: Ajay Devgn and Kajol at an event in Mumbai
Photos: Sonakshi Sinha, Sushant Singh Rajput at Mumbai airport
Pics: Prabhas, Tamannaah Bhatia at 'Baahubali 2' first look launch at MAMI
'Ae Dil Hai Mushkil' photos: Aishwarya, Anushka, Karan get candid at MAMI
Photos: Huma Qureshi, Neha Dhupia and other celebs at MAMI