The body was first spotted by residents of Hetu village under Jaggannathpur police station area in the outskirts of the state capital.
"It (human sacrifice) is the point of our investigation. But there could be other reasons behind the murder," said Prabhat Kumar, senior superintendent of police (SSP), Ranchi.
He added that the police are also waiting for the postmortem reports to ascertain if the victim was sexually assaulted before being murdered.
A search operation was also launched by the local police and villagers to recover the head of the victim.
The SSP added, "We have alerted all police stations to find out if any girl aging between 18 and 25 has gone missing from their respective police stations."
"The reasons behind the murder would be clear once we identify the victim," said Kumar.