The special court in New Delhi is under a media blackout, but Indian media reported that the court began hearing evidence from several witnesses to the Dec. 16 attack, which has focused international attention on violence against women in the country.
BBC reporter Sanjoy Majumder told CBC News that one of the first witnesses to arrive at the courthouse was the young male friend of the student, who was with her the night she was allegedly gang-raped by five men on a bus and is now in a wheelchair after he too was attacked.
The woman and her friend were dumped naked at the side of the road, and the woman died two weeks later in a Singapore hospital.
There is a publication ban on the trial, but in earlier statements, the woman's friend said he tried to stop the assault, but instead was attacked with iron bars as they dragged her to the back of the bus.
He has also pointed fingers at the police, freelance journalist Faiz Jamil told CBC News. He has said that after he and the woman were dumped on the side of the road, three police vans showed up, but instead of helping them, the police argued over whose jurisdiction they were under.
Majumder said some of the other witnesses set to appear Tuesday were the first people at the scene to help the student and her friend, who boarded the bus after watching a screening of Life of Pi.
Accused proclaim innocence
The five accused signed statements in fast-track court, saying they were innocent of the 13 charges against them, one of the men's lawyers said on Saturday. The lawyer cannot be identified under a gag order imposed by the court.
A sixth suspect, who is 17 years old, will be tried in a juvenile court and could face a maximum sentence of three years in a reform facility if convicted.
The six suspects, the only occupants of the bus, beat the man with a metal bar, raped the woman and used the bar to inflict massive internal injuries to her, police say.
The incident set off mass protests, sparking a debate about the treatment of women in India and highlighting the inability of law enforcement agencies to protect them.