The convict, Renjit, killed the girl after conniving with minor's daughter and his friend Basil.
Renjit and minor's daughter Rani had been in relationship and the two wanted to remove the girl who was being a hurdle to their affair.
Basil and Rani have been awarded double life term.
Following his conviction, Renjith tried to commit suicide in the jail on January 10.
According to the chargesheet, the child was sexually assaulted too before being murdered. (ANI)