Ashok was granted bail on furnishing a Rs 50,000 bail bond.
Pradhuman, aged seven, was found on September 8 morning in the washroom of the Ryan International school in Bhondsi area on Sohna Road with his throat slit.
The Gurgaon police had arrested Kumar, pinning the blame for the crime on him, claiming that he murdered the child after failing to sodomise him.
Two school staff and Ashok's family however claimed he was made a scapegoat since he was poor.
In a twist in the case, the CBI recently announced that it had apprehended a senior student of the school in connection with the incident, rejecting the police theory that the killing of Pradhuman was the handiwork of Kumar.
The arrested 16-year-old has been lodged in Faridabad's observation home. Ashok was in jail even after the arrest of the school student.
(With inputs from agencies)