(CNN) -- The man who was accompanying a New Delhi woman when she was gang-raped in December testified Tuesday as the trial of five men accused of attacking her formally began.
The man was the only one of 86 witnesses to testify on the opening day of testimony in the trial, which is being held in a "fast-track" court designed to cut down on red tape.
He will be cross-examined Wednesday, prosecutors said.
Under a judge's order, media outlets are limited in what they can report about the case, including details of testimony.
The five men are charged with murder, rape and kidnapping. They could face the death penalty if convicted.
A sixth suspect is 17 and will be tried separately in juvenile court.
According to New Delhi authorities, the suspects attacked the woman -- a 23-year-old medical student -- and her male companion on a bus, robbed them and dumped them by the side of the road.
The woman was badly injured in the attack. She died on December 29 after being flown to Singapore for treatment.
Prosecutors expect to finish presenting their case within a month, court officials said.
The case has gripped India and led to calls for stricter laws on sexual assault and changes in cultural attitudes toward women in India, where most women have stories of sexual harassment and abuse on public transportation or on the streets, according to the Indian Council on Global Relations.
A panel appointed by India's home affairs minister as a result of the case criticized Indian attitudes toward sexual assault and called for policy changes, including creating a new offense of gang-rape punishable by at least 20 years in prison, making it a crime for police to fail to investigate sexual assault complaints and making it illegal to consider character or previous sexual experience of the victim at a criminal trial.
Journalist Neiha Sharma contributed to this report.