Rapists of 23-year-old victim charged with murder in Delhi (UPDATE)

The six men arrested for the brutal gang rape of a 23-year-old medical student have been charged with murder, and face the death penalty if convicted. 

A police officer was suspended by state authorities, and two more fired, over accusations that they put off the investigation and delayed the suspects' arrests, the Associated Press reported.

Three of the men accused were only arrested Thursday, nearly a month after the crime was reported, according to the AP. 

“This is a very sensitive crime, I have taken it very seriously,” said Paramjit Singh Gill, a head police officer in the city of Patiala.

The 23-year-old woman, who has not been identified, died at 4:45 am on Dec. 29, in a Singapore hospital with her family by her side.

Her body arrived back in New Delhi later today, Sky News reported.

The brutal rape has sparked mass protests in India's capital, Delhi, as thousands took to the streets.  

Indian leaders appeared for calm, and tried to prevent unrest by turning Delhi "into a fortress," Agence France Presse reported. Hundreds of armed police sealed off large parts of central Delhi and stood guard near government buildings.

But some 4,000 people gathered at the Jantar Mantar observatory, one of the areas of Delhi where protests are still allowed, the BBC reported.

The woman was raped aboard a bus by the men for nearly an hour, beaten with an iron rod and cut with a knife before being dumped on a roadside in southwest Delhi, after she and a friend sought to take the private bus home from a movie theater.

She was flown to Singapore for emergency treatment, but had been in an extremely critical condition since her admission to Mount Elizabeth Hospital, a statement from hospital chief executive Kelvin Loh said.

"She had suffered from severe organ failure following serious injuries to her body and brain," the statement said.

"She was courageous in fighting for her life for so long against the odds but the trauma to her body was too severe for her to overcome. We are humbled by the privilege of being tasked to care for her in her final struggle."

Indian authorities have announced various legal and security measures in a bid to be seen to be tackling India's rape crisis, including a plan to publicly name and shame rapists.

But so far the country's leaders have failed to address broader cultural problems, according to GlobalPost's Jason Overdorf — for example, the fact that "every major political party has fielded and continues to field candidates facing criminal charges for rape, harassment and other crimes against women."

More from GlobalPost: India: To stop rape, start at the top