Describing the modus-operandi of the crime, SSP Prashant Kumar said on January 9, accused Ravi, who is a friend of victim's father, had taken the girl to the market on the pretext of getting her some eatables.
However Ravi, a drug addict, took the girl to a secluded place, where he raped and fatally struck her with a brick, Kumar said.
He told police that he was in an inebriated condition when he committed the crime, Kumar said.
Post-mortem report of the girl, whose body was found on January 10 on the Nandgram-Sihani Road, had confirmed she was raped before being murdered.
The incident had sparked violent protests in the area, resulting in injuries to several people, including policemen.
BJP leader and local MP Rajnath Singh had also visited the victim's family after the incident.
Kumar said the accused also had taken part in the protest to evade suspicion.