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.

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.

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.

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

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 former civic police volunteer was sentenced to life imprisonment by the Sealdah Civil and Criminal Court in Kolkata on Monday.

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