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.

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.

Additional sessions judge Mamta Bhojwani said the crime was “extremely perverted, heinous, brutal and cowardly”