New Delhi: Early in January, just days after the medical student they were accused of raping died in a Singapore hospital, the five men in Tihar Jail accused of raping and murdering her appeared to be depressed and were on "suicide watch," jail officials had said.
A sixth suspect, who was underage, had been kept at a juvenile home and was being tried separately.
Early this morning, Ram Singh, 33, the main accused, hanged himself in his cell.
In January, Authorities at Tihar Jail said the five men there "just sit and brood."
A senior officer had been told to monitor their activities.
"We are putting all kinds of check on them to keep them away from (committing) any untoward incident. They are basically on suicide watch," a jail official had told news agency IANS, speaking on condition of anonymity.
Ram Singh was known to be prone to violence, jail officials said.
Before he was arrested, he lived in South Delhi with his brother, Mukesh. On the night of December 16, he allegedly decided to take the school bus he drove everyday for a spin with his friends. The police says Mukesh was driving the bus when the six men on board saw a young girl and a man waiting at a bus stop.
The couple thought the bus was the sort of privately-owned vehicle used by thousands of commuters in Delhi everyday. After they climbed on board, the men allegedly battered them with an iron rod, before taking turns to rape Amanat (Not her real name).
When they were thrown onto the road an hour later, the police says Ram Singh urged tellers to run over Amanat, but her friend managed to push her of of the way.
The attack stirred grief and anger, with thousands holding street protests in different cities to demand a speedy trial for the accused, and better safety ad public transport for women.
There was outrage in India, with protesters demanding the death penalty for the accused and changes in rape laws.
The trial for Ram Singh and the other adults was held in-camera or behind closed doors. 40 of nearly 80 witnesses for the prosecution ave testified so far, including the software engineer who was with Amanat on the bus.