Behind a barbed wire-topped wall by a busy New Delhi highway a teenager sits alone in a locked room, accused of taking part in a gang rape that first sparked nationwide protests and now a debate over whether law in India is too lenient on juveniles.
Police allege the youth and five men lured a 23-year-old trainee physiotherapist and her male friend onto a bus where they repeatedly raped her and beat her with a metal bar before tossing the bleeding couple onto a road.
The woman died of internal injuries two weeks later.
Reuters has learned that officials at a juvenile detention facility in Delhi have taken the unusual step of keeping the teenager isolated from other detainees for his own safety.
They say the brutality of the attack angered the other inmates, some of whom have been convicted of murder.
Two officers from the team responsible for the youth's care have for the first time described in detail to Reuters the youth's life in the unit for violent young offenders since his arrest in connection with the December 16 rape.
The officers said the youth had proclaimed his innocence and blamed his co-accused.
"He says he has done nothing, the others have committed this crime," one of the officers said.
He has been assigned a defence lawyer under legal aid. His lawyer declined to comment on his client's guilt or innocence when approached by Reuters.
Authorities have not publicly disclosed any details about where the teenager is being held or the conditions in which he is being kept.
While his co-accused have been seen entering closed-door pre-trial hearings, the youth has been kept out of the media spotlight since his arrest at a New Delhi bus station on December 21.
Officials have also told how the youth was taken to hospital just days after his arrest, complaining of acute abdominal pains.
He was diagnosed with appendicitis and immediately operated on, according to three people, including a hospital official, with knowledge of his case.
All the officials interviewed spoke on condition of anonymity because of the sensitivity of the case, which in December brought thousands of protesters onto the streets demanding better protection for women in a country where police say a rape is reported every 20 minutes.
Reuters was not permitted to enter the youth detention facility, which is wedged between the polluted Yamuna river and a six-lane road in the smoggy north of New Delhi.
Through the gate of the grimy yellow-coloured compound, small buildings and a treeless concrete courtyard could be seen.
The teenager has been mostly confined to a single room of the unit, two officers responsible for his care said. Most other inmates stay in rooms of two to four people.
The unit is reserved for offenders serving time for violent crimes who are considered a danger to inmates in other detention centres.
The boy is kept away from other detainees, who would attack him if they could, the officers responsible for his care said.
"They watch the television in the dormitories and get very angry when they see news of the rape," one of the officers said.
The youth is to be tried separately from his five adult co-accused. Their trial began on Tuesday. A Juvenile Justice Board comprising a magistrate and two other members will hear his case on February 14.
If found guilty, he will face a maximum of three years in juvenile detention because he was under the age of 18 at the time of the crime.
That has sparked debate about the leniency of Indian law on juvenile offenders. His co-accused face the death penalty.
Last week, authorities ruled he was 17, citing school records. However, questions remain about his age, in part because his mother says she does not know how old he is.
The officers described the teenager as introverted but bright. He is attended to health workers and is visited by a psychologist twice a week, they said.
He is not taking part in the daily exercise and education routine of other detainees. There is no television in his room and the officers say he is barely literate so he does not read.
The officers say they sometimes play ludo and other board games with him to give him some company.
The emergency operation the teenager underwent one night in December has left him with a six-inch scar on his abdomen. The pain has prevented him from performing daily prayers, the officers said.
An official at the government hospital confirmed the operation and said the youth was hospitalised for five days.
The officers said the boy showed no signs of physical harm when he arrived at the detention centre and had not reported being mistreated in police custody.
The youth, who the officers describe as short and frail, left home when he was 11 and got work in a roadside eatery, his mother told Reuters in January.
At first he sent about $12 a month home, but that stopped years ago, she said. In recent years he lived as a semi-vagrant, washing buses and collecting fares, according to a police report.
India's juvenile justice laws have evolved over the past decade and are now in line with UN norms focused on humane treatment of minors. India has raised the minimum age teenagers can be tried as adults to 18 from 16.
In response to the public outcry after the rape, the government last week fast-tracked new, tougher penalties for sex crimes. But it has resisted calls to return the adult age to 16.
Amod Kanth, a former Delhi police chief who helped draft the laws, said the youth had been unfairly judged by the police and media before a trial had taken place.
Kanth said it made no sense to change laws on the basis of one case.
Some 33,000 crimes were committed by juveniles in India last year, the highest number in a decade, but there has not been a large spike. Juveniles commit a tiny proportion of total crimes and far less than other nations such as the United States.
The detention centre officers are still unsure about the youth's age, even after a January 28 justice board ruling he was six months away from his 18th birthday at the time of the attack. Like millions born into poverty in rural India, the youth has no birth certificate.
Authorities often turn to teeth or bone examinations to estimate age, but these are generally only accurate within a couple of years. In cases where there is doubt, magistrates are required to accept the younger age.