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 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.

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.

The court also ordered Roy to pay Rs 50,000 as fine and directed West Bengal government to pay Rs 1,700,000 as compensation -- Rs 1,000,000 for death and Rs 700, 000 for rape on duty -- to the victim's family.

Sealdah Court in Kolkata has pronounced life imprisonment to the convict Sanjay Roy in the RG Kar Hospital rape-murder case. Sealdah Court in Kolkata found Sanjay Roy guilty of the brutal rape and murder of the trainee doctor at the premises of RG Kar Medical College & Hospital.

An Indian court has sentenced the man convicted of raping and murdering a female doctor at a Kolkata hospital to life in prison.

The BJP on Monday criticised the sentence of life imprisonment for the convict in the RG Kar rape-murder case by a Kolkata court as a "travesty of justice", and said justice must not only be done but also be seen to be done.

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