The alleged ringleader is a 35-year-old widower from the Ravi Dass colony, a slum in south Delhi. Police and neighbours describe him as a rowdy, heavy drinker. He was the regular driver of the white private bus alleged to have been used for the crime, which was normally used to ferry school children.
Originally from the western state of Rajasthan, police say he and friends had eaten a meal together and had been drinking heavily before deciding to take the bus out for a night-time joyride.
The 26-year-old brother of Ram Singh of the same address who worked as an occasional driver and cleaner of the bus. He is accused of taking part in the rape as well as hitting the woman and her boyfriend with an iron rod.
A 20-year-old gym assistant and fitness trainer, who has apparently confessed to beating up the boyfriend but denies raping the girl, according to The Hindu newspaper.
A 28-year-old helper on the bus, from the eastern state of Bihar. He was arrested in Bihar on December 21. He is also accused of trying to destroy evidence by helping to wash the bus after the incident.
A 19-year-old fruitseller, reported by The Hindu to have said "I have done a horrible thing... I have done a bad thing" during an earlier court appearance when police sought permission for an identification parade.
Suspect No 6
A minor whose name cannot be given for legal reasons. Thought to be 17, police are checking his age with a bone test.