Here is a timeline of the major events leading up to sentencing Friday of four adults for the fatal gang rape of a 23-year-old student on a New Delhi bus last December.

December 16, 2012: The physiotherapy student goes out for an early evening screening of the "Life of Pi" at a cinema with her male friend at an upmarket shopping mall in south Delhi.

Unable to track down a taxi or auto rickshaw, they are tricked onto a white private bus at around 9:00pm which they believe will take them back home.

Inside, a group of six draw the curtains, beat up and rob the male friend and then take turns in raping the girl as the bus drives around the capital.

After more than an hour, the bloodied young couple are dumped by a main road leading to the international airport, narrowly avoiding death when the gang try to reverse over them with the vehicle.

December 17: Police open a case and begin viewing CCTV footage from cameras fitted outside hotels, offices and government buildings. They identify a white bus with a missing wheel cap and "Yadav" written on both sides.

The driver of the bus Ram Singh is arrested. Inside the vehicle, the seats and curtains have been washed.

Police say forensic experts find strands of hair belonging to the victim and some of the attackers in the bus.

December 18: Fuelled by wall-to-wall television coverage and front-page newspaper articles, large numbers of women, students and other protestors hold demonstrations as the rape victim battles for life on a ventilator.

December 22: Police use batons, water cannon and tear gas on angry crowds who gather at the India Gate memorial in the heart of the city and outside the president's official residence.

All six accused have now been arrested and remanded in police custody.

The government sets up an inquiry to suggest ways to enhance women's safety in Delhi.

December 24: Two Delhi police officers are suspended for failing to halt the bus at checkpoints designed to stop suspicious vehicles. Roads across central Delhi are blocked as protests continue.

December 26: The gang-rape victim is airlifted to Singapore's Mount Elizabeth Hospital after her condition deteriorates in Safdarjung Hospital in Delhi. In one of many operations, doctors in India remove her intestines which were damaged when she was violated with an iron bar.

December 29: The woman dies from organ failure in Singapore, spurring more protests in New Delhi.

January 28, 2013: The Juvenile Justice Board declares one of the rapists is a minor, sparking a fierce debate about the criminal justice system for under-18s and demands for him to stand trial as an adult.

February 2: The five adult accused are charged with a string of offences, including murder, gang-rape, kidnapping and robbery. They are sent to judicial custody in Tihar Jail. Three weeks later, the juvenile is charged with the same offences.

March 11: Ram Singh, the main accused and a public hate-figure, is found dead in his cell after an apparent suicide. His family and lawyer allege murder.

March 21: India's parliament completes the passing of a tougher rape law which includes a provision for the death sentence if the victim dies. It also provides for a minimum 20-year prison sentence for gang rape.

August 31: The juvenile suspect is found guilty of rape and murder and sentenced to three years in a correctional facility -- the maximum possible sentence for the teenager under Indian law.

September 10: The four adult suspects -- Mukesh Singh, Vinay Sharma, Akshay Thakur and Pawan Gupta -- are found guilty of all charges. The judge says they committed a "cold-blooded" murder.

September 13: Judge Yogesh Khanna is set to deliver the sentence under enormous public and political pressure for the death sentence.