The assailants shot the criminal from point blank range and when the Delhi Police personnel, who had brought him here, tried to chase the killers, they took out pistols to scare them, SSP Preetinder Singh said.
Singh said the assailants tried to run away from Gate Number 2 towards the back of the collectorate.
Some advocates, however, gave a chase and managed to capture one of them, he said. The person has been arrested.
Anand was lodged in Tihar Jail in Delhi in connection with several cases of crime in the national capital. He was arrested by the Delhi Police a few months ago.
"We have requested for proper security and safety at the district courts. There is lack of security personnel at the gates. Metal detectors too are non-functional. CCTV footage will help the police in investigation," Bar Association Secretary Sardar Singh Bansal said.