The main suspect in the gang rape and fatal beating of a woman on a New Delhi bus, an attack that horrified Indians and set off national protests, committed suicide in jail Monday, police officials said.

Ram Singh, who is accused of driving the bus on which the 23-year-old student was raped and fatally assaulted by a group of six men in December, hanged himself with his own clothes, said G. Sudhakar, the top police official at Tihar jail.

Singh, along with four other men on trial with him on rape, murder and abduction charges, had been under a suicide watch, another jail official said on condition of anonymity because he was not authorized to speak publicly on the matter. He said the five were being held in separate cells in separate buildings at the jail.

If convicted, the men could face the death penalty. The sixth accused is being tried and jailed separately because he is a juvenile.

Singh's lawyer, A. P. Singh, confirmed his client's death, saying he died at 5:30 a.m. He alleged that police maleficence led to his client's death.

"What do you mean killed himself? He has been killed in prison," Singh said.

Lawyers for the men have previously accused police of beating confessions out of their clients.

Indian jails have a reputation for overcrowding, poor management and brutal treatment of inmates.

The woman and a male friend were attacked after boarding the bus Dec. 16 as they tried to return home after watching a movie, police say. The six men, the only occupants of the private bus, beat the man with a metal bar, raped the woman and used the bar to inflict massive internal injuries to her, police say. The victims were dumped naked on the roadside, and the woman died from her injuries two weeks later in a Singapore hospital.

The brutal attack set off nationwide protests about India's treatment of women and spurred the government to hurry through a new package of laws to protect them.

Singh's death comes as the trial was deep underway, with another hearing scheduled for Monday. There was no word if that would be affected.