The torso of the girl was found on October 24 and a day later her severed arms were recovered, according to police.
Her head was found today in the Ateli area, about 50 kms from here, they said, adding the minor's post mortem was conducted at PGIMS, Rohtak.
The Class VII student was kidnapped by unidentified persons on October 20 and four days later her torso was found, triggering protests by the family members and villagers.
The protest was called off following a request of DSP Jaipal Singh, who assured of a speedy action into the matter.
A case of murder was registered and probe initiated into the matter, police said.