He was 17-and-a-half, the youngest of six men who raped and brutally tortured a 23-year-old medical student on a moving bus in the capital on December 16, 2012. She died 13 days later in hospital.
Four other men found guilty in the case are on death row. One died in jail.
The 21-year-old is reportedly afraid of returning to his village in Uttar Pradesh. He fears for his life because of the gravity of the crime he committed.
He has been given professional counselling after he was allegedly radicalised by another boy lodged at the centre for the 2011 Delhi High Court blast that killed 15. Sources said the other juvenile, from Kashmir, was "brainwashing" him to join jihad.
Though he is an adult now, the law says the young man's name or identity cannot be revealed.
His release from the home comes as a debate is raging again on whether the age at which a person can be tried in court for a crime should be lowered to 16 from 18, after a two-and-a-half year child was brutally raped, allegedly by two minors in the capital.
At the centre, superintendent Premoday Khakha says, "I feel a person can be transformed at any age and we can't punish all minors harshly for a heinous crime committed by a few".
Mr Khaka, who has for the last three years observed the young man accused of a crime that shook the conscience of a nation, says, "The maximum number of boys found violating the law are those who come from deprived sections and those who have no support from family or society."
NDTV learned that almost 20 per cent of the children lodged in juvenile centres have nowhere to go when they are released. They have either run away from home years ago or been abandoned by their families.
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