The four men set to be sentenced Friday over the December 16 New Delhi gang rape were economic migrants on the bottom-rung of the capital's social ladder, drawn to the city to escape grinding rural poverty.

All the rapists lived in and around Ram Dass Camp, an unauthorised slum in the south of the city favoured by hundreds of labourers whose homes are mostly without toilets or running water.

Residents there complain of the ignominy of being associated with the men, particularly the ringleaders whom they remember as heavy-drinking troublemakers known for their abusive language and disregard for neighbours.

Ram Singh, the regular driver of the bus used for the attack and the ringleader according to police, was found hanging in his prison cell in maximum-security Tihar jail on March 12 in a suspected suicide.

The 32-year-old had confessed privately to his role, according to his parents, but during the trial he had denied the long list of charges including murder, rape and kidnapping.

Here are profiles of the four men convicted, as well as the fifth under-age suspect who was sentenced to three years in a correctional facility on August 31.

MUKESH SINGH

The brother of Ram Singh who migrated to New Delhi from his ancestral village in the western desert state of Rajasthan. He frequently worked with his brother on the bus but was unemployed at the time.

During court proceedings in April, the unmarried labourer, who has a tattoo of two swords signifying "bravery" on his left arm, told AFP he was a "very hard working man" and wanted to "lead a simple life".

Aged 29 at the time of the crime, he denied the most serious charges against him and said he was driving the bus at the time of the attack but did not take part.

He told the court that he "respected women".

VINAY SHARMA

Aged 20 at the time of the crime, he denied being on the bus. He earned $100 a month as a helper at a local gym and lived in the same neighbourhood as Mukesh and Ram Singh.

He had completed his schooling, unlike the other convicts who are school dropouts, and during the trial said he wanted to appear for a recruitment test for a job with the Indian Air Force.

Sharma submitted an application to the judge to be moved out of Tihar jail after being assaulted by inmates. He suffered a fractured left hand while in custody.

PAWAN GUPTA

The youngest of the adult rapists, aged 19, Gupta was a fruitseller who also worked as a labourer on roads and construction sites for a couple of dollars a day. During wedding season, he would work with a catering company.

He was arrested at the Ram Dass Camp where he lived with his cousin and was known as a friend of Ram Singh.

AKSHAY THAKUR

A married father of a two-year-old son, Thakur also worked as a helper with Ram Singh and had earlier been employed in a local liquor factory and in a brick kiln.

Aged 28 at the time of the crime, he fled from Delhi on December 17, but was arrested at his father-in-law's home in the eastern state of Bihar.

UNDER-AGE SUSPECT

A 17-year-old at the time of the attack, who cannot be named for legal reasons, is a run-away who fled his home in impoverished Uttar Pradesh state at the age of 11.

His mother told the police that he was the eldest of her six children and that she had no contact with him during his time in the capital where he had no fixed job or address and often slept rough.

He cleaned Ram Singh's bus and in winter slept inside the vehicle.