India's minister of home affairs promises inquiry after Ram Singh, on trial for rape, was found hanged in his prison cellIndia's home minister has admitted a "serious security lapse" after the man accused of leading five others in the brutal gang rape and murder of a 23-year-old physiotherapist in Delhi in December was found dead on Monday morning in the high security prison where he was being held during his trial.Sushilkumar Shinde, the minister of home affairs, promised an inquiry after the apparent suicide of Ram Singh, who was found hanged by his own clothes and a prison blanket at 5am, officials at Delhi's Tihar jail said.Singh, 34, was on trial with five others at a specially established fast track court in Delhi and faced the death sentence for his part in the gang rape and murder, which took place on the bus he drove for a living.The Indian government has been repeatedly criticised for its handling of the case and its aftermath.