11 March 2013 Last updated at 11:56 ET

Delhi rape case accused Ram Singh's death 'a lapse'

The BBC's Sanjoy Majumder reports from Delhi: "He was kept in a cell along with two others"

The death in prison of a suspect in the rape and murder of a female student in India's capital, Delhi, was a major lapse in prison security, Indian Home Minister Sushilkumar Shinde has said.

Mr Shinde said action would be taken, and promised an investigation.

Police say Ram Singh hanged himself in Delhi's Tihar jail, but defence lawyers and his family suspect he was murdered.

Mr Singh, 33, was one of five men being held in the case, which outraged India. They all deny the charges.

A sixth suspect is being tried by a juvenile court.

The BBC's Sanjoy Majumder, in Delhi, says Mr Singh's death comes as a huge embarrassment for the authorities who are already under enormous pressure over the case.

'No suicide watch'

Mr Shinde said the authorities would respond only after the enquiry had reached its conclusions, probably in two or three weeks' time.

"It is a major lapse in security, certainly it is not a small incident. Action will be taken," Mr Shinde said.

Tihar jail spokesman Sunil Gupta told the BBC that Ram Singh appeared to have hanged himself with an improvised rope made from a blanket at about 05:00 local time on Monday (23:30 GMT Sunday).

V K Anand, defence lawyer for Ram Singh: "There has to be some foul play here"

He said Mr Singh had not been on suicide watch, and had been able to make a noose and attach it to a metal grille while his three cellmates were asleep.

His body would be taken for a post-mortem examination later on Monday, Mr Gupta added.

Ram Singh's lawyer, V K Anand, told reporters he was informed about his client's death by police.

"There has to be some foul play here," he said.

"There were no circumstances which could have led to Ram Singh committing suicide. There was no mental stress. He was very happy... The trial was going on very well."

Mr Singh's father, Mangelal Singh, said his son had a badly injured hand and could not have hanged himself.

Ram Singh's death in India's most secure jail is a huge embarrassment for the authorities

He also said his son had been raped in prison by other inmates, and repeatedly threatened by prisoners and guards.

"My son has not committed suicide," he said.

Nationwide protests

Ram Singh and the four other adult defendants - his brother Mukesh, Pawan Gupta, Vinay Sharma and Akshay Thakur - have been on trial in a fast-track court.

The case was due to resume on Monday. Reporting restrictions mean few details of the trial have been made public.

They face 13 charges, including murder, gang rape, kidnapping and destruction of evidence. If found guilty they could face the death penalty.

Case Timeline

• 16 December 2012: Student gang raped on Delhi bus
• 17 December: Bus driver Ram Singh and three others arrested
• 18 December: Uproar in parliament, street protests in Delhi and elsewhere
• 21-22 December: Two more arrests, including a minor
• 29 December: Victim dies in Singapore hospital
• 7 January 2013: Suspects charged in court with abduction, gang rape, murder
• 21 January: Trial of five accused begins in special fast-track court
• 2 February: Five accused plead not guilty
• 28 February: Sixth accused charged in juvenile court
• 11 March: Ram Singh found dead in Tihar jail

• Profile: Delhi rape accused Ram Singh
• India jail death sparks reaction

The maximum sentence the juvenile would face if convicted would be three years in a reform facility.

The 23-year-old rape victim, who was not named for legal reasons, was with a male friend when she was attacked on a bus and thrown from the vehicle on 16 December.

She died in a Singapore hospital on 29 December from massive internal injuries.

Ram Singh was accused of being the driver of the bus.

The case provoked nationwide protests and demands for tougher penalties for rapists, as well as greater protection for women.

Tihar prison, which authorities say is the largest in Asia, is India's most high-security prison.

The 55-year-old jail houses more than 12,000 inmates, although it has an official capacity of about 6,000.

The complex includes nine separate prison facilities.

Media reports quoting the chief of Tihar prison Vimla Mehra say there were 18 deaths in the jail last year, of which two were cases of suicide.