Four men sentenced to death for the gruesome gang rape and murder of a woman on a New Delhi bus in 2012 were hanged Friday, concluding a case that exposed the scope of sexual violence in India and prompted horrified Indians to demand swift justice.

The four stood trial relatively quickly in India's slow-moving justice system, their convictions and sentences handed down less than a year after the crime. India's top court upheld the verdicts in 2017, finding the men's crimes had created a "tsunami of shock" among Indians.

The victim, a 23-year-old physiotherapy student, was heading home with a male friend from a movie theater when six men tricked them into getting on a private bus. With no one else in sight, they beat her friend and repeatedly raped the woman. They penetrated her with a metal rod, causing fatal internal injuries. They dumped both victims on the roadside, and the woman died two weeks later.

Asha Devi, the mother of the victim, thanked the judiciary and government after the convicts were hanged.

"Today, we got justice, and this day is dedicated to the daughters of the country," she told reporters. "I could not protect her, but I was able to fight for her."

Devi said she hoped that courts in India will end delays in rape cases and punish convicts within a year's time.

The case drew international attention at the time and prompted Indian lawmakers to stiffen penalties for rape, part of a wave of changes as India confronted its appalling treatment of women.

Facing public protests and political pressure after the attack, the government reformed some of India's antiquated laws on sexual violence and created fast-track courts for handling rape trials that formerly could last more than a decade.

The new laws prescribed harsher punishments for rapists and addressed new crimes, including acid throwing and stalking.

India’s prime minister Narendra Modi said Friday that justice had prevailed and it was of utmost importance to ensure the dignity and safety of women.