Indian police have said a teenage girl who was gang-raped twice in Kolkata last October had died after she was set on fire by her aggressors.

Police Commissioner Santosh Nimbalkar said on Thursday that before her death, the 16-year-old girl from Bihar gave a sworn statement claiming that she was set on fire by two people, who had earlier abused her.

The victim's family told police that following their daughter's rape, friends and family of the accused continually harassed and even threatened them to withdraw the case.

"Goons hurled abuses and said they would kill us," the mother said. "Policemen watched this silently. What is the use of policemen who cannot protect us?"

Then on December 23, she was set on fire, dying in hospital a week later.

The girl's body is in the custody of her family.

Until Thursday, police were treating the girl’s death as a suicide. But now, they said they are treating it as murder, after disclosing they recorded a death-bed statement by the victim.

The victim's family are now demanding that the rapists be sentenced to death, local media reported.

Police in the northern state of Bihar said they had spoken to the girl's family, and asked them what kind of assistance they required, Abhayanand, director-general of Bihar Police, said.

"We will meet them and ask them how the police can help," he said. "We will also request the West Bengal police to proceed with the investigation into the incident."

India, with its poorly trained police force and clogged courts, is struggling to curb violence against women.

Huge public outcry

In December 2012, a gang-rape in New Delhi led to a huge public outcry, that forced the government to pass stronger laws against rape and other crimes against women.

Since then there has been a sharp increase in the reporting of rape cases to police.

But so far, there is no indication of whether the tougher laws have led to a decrease in the number of crimes committed against women.

Against this backdrop, Mohammed Salim, leader of the opposition Communist Party of India-Marxist, blamed the West Bengal government, the police and health departments for their negligence that led to the death of the teenager.

"It is a deliberate attempt for murder, murder by the police authorities," Salim said. "That's why I don't think that any victim has the confidence now in the state administration that justice can be ensured."

Voicing her concern, Mamta Sharma, chairperson of India's National Commission for Women, urged the West Bengal government to take a serious look into the incident.

"The police should have given her some protection," she said.  "But there was no protection for her and she was raped once again and subsequently she was killed."

Source: Al Jazeera and agencies