The crime shook the country, stirred global outrage and brought focus on India's attitudes and treatment of women. The victim died of her injuries 13 days after the brutal attack.
"He has been moved to an undisclosed location, where he will be observed. But technically, he is no longer in custody," Delhi state government spokesman Nagendar Sharma told CNN on Sunday. The law states that the under-18 rapist cannot be named.
Under India's juvenile justice laws, a minor's maximum punishment is three years at a reform facility. The Indian government had opposed his release, but the New Delhi High Court on Friday refused to grant a petition for prolonged custody, government lawyer Anil Soni said.
On that day at the court, there were few clues that a momentous decision was underway in the watershed case. Besides a small band of lawyers and journalists, few were present when the court ruled he would be released.
'Crime has won. We have lost'
In 2013, when the men were convicted, Indians had demanded "fansi," death by hanging.
But in the cool breeze of this December day, the outrage that erupted from this case seemed a memory. The only expression of disappointment came from the victim's parents and the lawyers who had fought to delay the release.
The victim's mother, Asha Singh, had promised her daughter she would fight for her. But on Friday, she said she had failed.
"Crime has won. We have lost," Singh said. "Our efforts for three years have failed."
"If they understood my daughter's pain, if they understood my pain," she continued, "the culprit would not be free."
"He deserves the same punishment as the four who've been given the death penalty. It should set a historic example in society that if you treat women and girls this way, no one will be spared."
Of the other five rapists, one died in prison
and the other four received death sentences
India's juvenile justice laws were drafted with the best of intentions and aimed at reform for minors.
In the aftermath of the gang rape, a bill introduced in Parliament sought to amend the law to make exceptions to the three-year sentence limit in cases of heinous crimes. But that bill was tabled in the upper house.
Indian law enforcement and lawmakers had asked for continued custody of the minor, who has been held at an institution for juvenile reform. But the high court could not find legal ground on which to issue a stay.
"The court is no doubt concerned by what has happened and the seriousness of the offense, but the court is also helpless because they have to stay within the confines of the act and the rules and the law," said Soni, the government lawyer.
A three-year sentence seemed vastly disproportionate given the nature of the rape. The crime was unimaginably brutal. On the night of December 16, 2012, the victim and a male friend boarded a bus to make their way home from a south Delhi movie theater, not far from the high court complex. They were attacked by the six men and left on the side of the road to die.
The woman was found with her intestines pulled out of her body. She was dubbed "Nirbhaya," one without fear, as she struggled for survival, first in Delhi and then in a hospital in Singapore. She died of her injuries 13 days later.
On Wednesday, people gathered at a third anniversary commemoration in Delhi and listened to Asha Singh name her daughter publicly for the first time -- Jyoti Singh. By law, rape victims are not ever named publicly in India.
"Why should I hide her name? Why should I be ashamed of it?" her mother said. "Those who committed that heinous crime on her should feel ashamed. The makers of this administrative system should feel ashamed."
'Public memory is fickle'
The crime galvanized Indians to take to the streets. They demanded an end to violence against women and as well as legal and societal changes. But though the Nirbhaya case is still widely discussed, the fervor has calmed and few changes have materialized.
"Public memory is fickle," said Meenakshi Bhanja, 35, a Delhi-based journalist who was outside the Delhi court Friday.
"Has anything changed in India? I am sorry to say, no," she said. "Outrage over an incident doesn't change the DNA of the society."
That was also the sentiment of three young women, all law students who are interning at the high court.
"Our legal system should be strong enough to make us all feel safe," said Dolly Kaushik, 22. "Nothing has changed in India."
Her friend Kritika Dua, 22, said India has the laws in the books, but she blamed the police and the judiciary for failing to implement them. Kaushik blamed all of Indian society.
"Even we are at fault," she said. "The mindset has to change. How can anyone say that the answer to the problem is that girls should not go out?"
She was referring to Indian politicians who, in the aftermath of Jyoti Singh's rape, suggested that she had perhaps asked for it by going out at night.
"In our country, fathers rape their daughters," Kaushik said. "Most rape cases happen in the house."
Monika Khatri, another 22-year-old law student, who wants to become a judge, said a young man who rapes a woman so violently that she dies from her injuries should serve many years behind bars, no matter his age. Justice, she said, had eluded Nirbhaya.