The CBI will file an appeal before the Calcutta High Court seeking death sentence for Sanjay Roy, who was sentenced to “life imprisonment until death” by a Sealdah court in the rape-cum-murder case of an on-duty doctor at RG Kar Medical College and Hospital, officials said Wednesday.

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.

An Indian court has sentenced a police volunteer to life in prison after finding him guilty in the rape and killing of a trainee doctor last year.

Sanjay Roy, a police volunteer, was sentenced to life in prison on Monday for the rape and murder of a trainee doctor attacked while on duty in Kolkata — a crime that sparked widespread protests across India.

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.

An Indian court on Monday sentenced a police volunteer to life imprisonment for the rape and murder of an on-duty doctor last year – a crime that sparked nationwide protests. Sanjay Roy, 33, plans to appeal the judgment in a higher court.

The police had sought the death penalty in a horrific but familiar crime. Its handling by the local authorities had outraged the nation.