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 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.

An Indian court on Monday sentenced a police volunteer to life in prison after finding him guilty in the rape and killing of a trainee doctor last year, a crime that sparked nationwide protests over inadequate safety for women and led to a speedy trial in the country’s slow-moving justice system.

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

The family of the doctor broke into tears, saying they were "shocked" at the sentence and had hoped her murderer would be sentenced to death.

A court in India has given the life sentence to a man for the rape and murder of a junior doctor, a crime that sparked nationwide outrage and protests. The judge rejected demands for the death penalty but said that Sanjoy Roy,