An Indian court awarded a life sentence on Monday to a police volunteer convicted of the rape and murder of a junior doctor at the hospital where she worked in the eastern city of Kolkata, rejecting demands for the death penalty and saying it was not a rare crime.

The decision to challenge the trial court’s sentence of life imprisonment came hours after the central agency opposed a similar plea by the state government.

India's West Bengal state launched an appeal on Tuesday to overturn a life sentence in favour of the death penalty for a police volunteer convicted of the rape and murder of a junior doctor, a senior lawyer aware of the development said.

A sessions court in Kolkata will pronounce today the quantum of sentence for Sanjay Roy. Follow The Hindu’s live updates

The CBI is likely to file the appeal against the Sealdah court order by Friday with detailed arguments in favour of capital punishment, they said.

A Kolkata court on Monday criticised the authorities at the RG Kar Medical College and Hospital and the police for attempting to cover up the murder of a junior doctor as a suicide, Live Law reported.

Soon after his conviction in the Kolkata doctor rape-murder case, civic volunteer Sanjay Roy's mother, Malati Roy, affirmed that she would accept the punishment given to her son by the Sealdah sessions court.

An India police volunteer was convicted on Saturday of the rape and murder of a junior doctor at a hospital in the eastern city Kolkata, local media reported, in a speedy trial of a crime that sparked national outrage over the lack of safety for women.

Trial court judge Anirban Das condemned the police and hospital actions in the RG Kar hospital rape-murder case, pointing out delays and attempts to cover up the crime. The accused was found guilty, with evidence showing his impulsive attack.