The 28-year-old software engineer, the prosecution's star witness, appeared in court in a wheelchair on Tuesday, still bearing the scars of injuries from the attack.
The December attack in India's capital provoked outrage and widespread protests calling for legal and policing reforms, as well as a shift in cultural attitudes.
The five accused include a bus driver, a cleaner, a gym assistant and a fruit seller. All have pleaded not guilty to charges of rape and murder. If convicted they face the death penalty. A sixth accused is being tried separately as a juvenile.
Police say the six attacked the 23-year-old trainee physiotherapist and her friend after enticing them aboard a bus as the couple returned home from watching a movie at a mall on December 16. The woman was repeatedly raped and repeatedly penetrated with at least one metal bar. The couple were also severely beaten before being dumped on a roadside near the Indian capital's international airport.
The woman died of massive internal injuries in a Singapore hospital two weeks later
In his statement to police after the assault, the friend gave a detailed account of events.
Call for attackers to be hanged
He said their attackers asked: "Where are you going with a girl so late at night?" Within moments of the couple boarding the bus before the gang launched its assault. Though he tried to protect the woman, he was beaten with a metal rod and restrained while his friend was repeatedly raped.
The police "charge sheet" also included confessions from the accused – which their lawyers say are either inadmissible or made under duress and thus worthless – as well as a statement from the woman, recorded by a magistrate, before she lost consciousness.
The prosecution says the accused shared out property stolen from the couple, including their cellphones. About 30 police officers were deployed outside the courtroom as the five accused arrived from the high security wing of New Delhi's Tihar jail wearing scarves or handkerchiefs to mask their faces.
As the trial got under way, the victim's father appeared at a news conference organised by the main opposition Bharatiya Janata Party to call for his daughter's attackers to be hanged.
There was anger that the juvenile among the accused may escape any lengthy sentence for his role in the attack.
The trial is set to last for several weeks. – © Guardian News and Media 2013