According to police, the minor, a student of Class X, was murdered on May 4 by her parents, who cremated the body on the same night.
Hemant, the father of the girl, mother Gayatri Devi, maternal uncle Karam Raj and another relative were arrested for killing the minor over her alleged affair with a classmate, they said.
It is alleged that the girl was strangled by them with her dupatta, while she was watching TV.
The girl's father had on April 11 filed a complaint about the alleged kidnapping of his daughter by the boy, police said.
The boy was arrested and the girl recovered on April 13, police said.