Upon being informed by locals, the girl's body was recovered by the police from a bamboo bush in Haripur Nawtolia village of Khagaria district.
The victim's body bore injury marks on her neck and vital parts indicating that she was raped and strangled to death, sources said.
The body, which is yet to be identified, was sent for post-mortem.
In the other incident, a seven-year-old girl was allegedly raped by a man at Nepura village in Nawada district last night.
On hearing the child's cries for help, local people rushed to the spot and took her to Sadar hospital where doctors referred her to Patna Medical College and Hospital in view of her serious condition, they added.
The accused was later arrested from his house and taken to the police station for questioning.
