The companion of a young woman who died after being allegedly gang-raped has identified the public bus on which the attack took place in the Indian capital while testifying in the trial of five adults accused of her murder.
The 28-year-old software engineer, confined to a wheelchair as a result of injuries sustained in the attack, confirmed that a white bus was the vehicle on which the deadly assault took place on December 16, his father said on Tuesday.
"Yes, my son could identify the bus. The cross-examination is going to start now," said the father, whose son cannot be named for legal reasons.
The victim's friend is the main witness in the case, which is being held in a special fast-track court in New Delhi's Saket district.
Although proceedings are subject to a gagging order, police allowed reporters to see the young man being taken in the company of lawyers and the judge to the bus which has been parked in the court compound.
No photographs were allowed.
The witness then returned inside the courtroom where he was expected to be cross-examined by lawyers for the five adult accused.
"My son will go to any lengths to ensure that the guilty are punished," the father had earlier said as the two of them entered the courtroom.
"He will cooperate and is prepared to answer any questions posed by the defence."
The five accused are Vinay Sharma, a gym assistant; Ram Singh, the bus driver; his brother Mukesh Singh; bus cleaner Akshay Kumar Singh; and fruit vendor Pawan Kumar.
They have pleaded not guilty to charges of rape and murder. A sixth accused is being tried separately as a juvenile.
The rape victim, a 23-year-old trainee physiotherapist, died in a Singapore hospital on December 29 from internal injuries she sustained during the alleged bus assault.
She and her companion had spent the evening at the cinema and were lured onto the off-duty bus after failing to flag down an autorickshaw to take them home, police say.
As well as taking turns to rape the woman and violating her with a rusty iron bar, the group allegedly attacked her friend so badly that he is still unable to walk properly.
The prosecution says articles stolen from the couple, including their mobile hones, rings and debit cards were found in raids conducted on the homes of the accused.
DNA evidence and bloodstained clothes also form part of their case.
Defence lawyers say they will highlight what they say are discrepancies in the account given by the victim's friend.
The judge has banned all reporting of proceedings inside the courtroom and ordered lawyers not to speak to journalists.
As the trial got under way on Tuesday, the victim's father made a surprise appearance at a news conference in New Delhi organised by the main opposition Bharatiya Janata Party (BJP) to call for his daughter's attackers to be hanged.
He spoke of the toll that the case had taken on him and reiterated his desire to see his daughter's killers hanged.
"I don't read newspapers or watch TV. I only want that all the six people should be hanged," he said.
"I have not been able to sleep for three days. I am running fever. I have pain in the legs."