The girl's body was fished out from a pond on Sunday - a day after her family reported her missing.
The case from Begusarai in Bihar comes close in brutality to that inflicted on a woman during a sexual assault in 2012.
The 26-year-old was taken to hospital with serious head and facial injuries and several fractures.
A Delhi high court order suspending the life sentence of former lawmaker Kuldeep Singh Sengar had led to outrage.
The court convicted six others, but cleared Dileep who was accused of orchestrating the assault.
The former temple cleaner's startling claims threw the town of Dharmasthala in Karnataka into turmoil.
Prajwal Revanna was found guilty of sexually assaulting a former employee.
Family members allege that the girl was kept waiting in an ambulance for hours before being admitted to the hospital.
Bajinder Singh, a self-styled pastor with millions of followers, was convicted for raping a woman in 2018.
