The minor was gang raped and later killed by some persons when she had gone to attend a marriage function on Thursday night and the body was recovered Friday, they said.
In another incident a 12-year-old girl was gang raped by three persons in Shivala Kalan area in Bijnor district Friday, police said.
An FIR was lodged against the accused Ritesh, Reenu and Arjun, they said.
Station House Officer Sunil Kumar Yadav said the girl was sent to the district hospital for medical examination where in the rape was confirmed.
He said that one of the accused Ritesh had been arrested.
In Badaun a six-year-old girl was raped by a 21-year-old youth in Binawar area yesterday, a senior officer said.
Additional SP Maan Singh said that the accused Annu had been arrested.