NEW DELHI (REUTERS) - Four men were found guilty on Tuesday of the rape and murder of a woman on a bus in the Indian capital, closing a chapter on a crime that triggered protests and soul-searching about the treatment of women in India.

Arguments on sentencing are due to begin on Wednesday and all four could be hanged for the murder conviction, said V. K. Anand, the defence lawyer for one of the accused.

They had all pleaded not guilty.

"All four accused committed on all sections," said Mr Anand.

Indian law prohibits naming the woman victim, a trainee physiotherapist from a lower-middle class family who had worked in a call centre, but Indian media have dubbed her Nirbhaya, a Hindi word meaning fearless.

The verdict capped a seven-month trial, often held behind closed doors, that was punctuated dramatically by a fifth defendant hanging himself in his jail cell. Outside the court, the case cemented India's reputation as unsafe for women, even after parliament passed new laws against sexual crimes.

Nirbhaya's case resonated with thousands of urban Indians who took to the streets in fury after the attack. Her path through education onto the first rungs of middle-class life seemed to epitomize the aspirations of millions of young women in the world's second most populous nation.

Bus cleaner Akshay Kumar Singh, gym instructor Vinay Sharma, fruit-seller Pawan Gupta, and unemployed Mukesh Singh were found guilty of luring the woman and a male friend onto the bus on the night of Dec 16 as the pair returned home from watching a movie at a shopping mall in south Delhi.

As the bus drove through the streets of the capital, the men repeatedly raped and tortured the 23-year-old with a metal bar before dumping her and her friend, naked and semi-conscious, on the road. She died in a Singapore hospital two weeks later of internal injuries.