An Indian police volunteer was convicted on Saturday of the rape and murder of a junior doctor at a hospital in the eastern city Kolkata, in the speedy trial of a crime that sparked national outrage over a lack of safety for women.

The woman’s body was found in a classroom at the state-run R G Kar Medical College and Hospital on August 9. Other doctors stayed off work for weeks to demand justice for her and better security at public hospitals.

Defendant Sanjay Roy said in November he was “completely innocent” and was being framed. He reiterated this in court on Saturday, saying, “I have not done this.”

Roy’s lawyers could not immediately be reached for comment on the verdict. They had argued there were glaring discrepancies in the investigation and forensic examination reports.

Judge Anirban Das said circumstantial evidence had proved the charges against Roy and that the sentence, to be announced on Monday, would range from life in prison to the death penalty.

“Your guilt is proved. You are being convicted,” the judge said.

The parents of the victim, who cannot be named under Indian law, expressed dissatisfaction with the probe, saying the crime could not have been committed by just one person.

“Our daughter could not have met such a horrific end by a single man,” her father said. “We will remain in pain and agony until all the culprits are punished.”

India’s federal police, who investigated the case, described the crime as “rarest of rare” during the trial and sought the death penalty for Roy.

Several doctors chanted slogans in solidarity with the victim outside the court. Dr Aniket Mahato, a spokesperson for the junior doctors, said street protests would continue “until justice is done”.

More than 200 armed police personnel were deployed in anticipation of the verdict as Roy was brought to court in a police car.

The investigation cited 128 witnesses, of whom 51 were examined during the trial, which that began on November 11 and was fast-tracked to conclude swiftly, according to court sources.

Police also charged the officer heading the local police station at the time of the crime and the then-head of the hospital with destruction of the crime scene and tampering with evidence.

The police officer is out on bail while the former head of the hospital remains in detention in connection with a separate case of financial irregularities at the hospital.