The attack was allegedly led by jailed gangster, Neeraj Bawania, who was one of the inmates present in the vehicle, accompanied by his cousins Naveen Bhanja, Naveen Bali and Rahul.
The incident was reported around 4.30 PM. Nine prisoners were being escorted to the jail in the prison van by two police officials - an assistant sub-inspector and a constable (driver) - both posted at the Third Battalion of Delhi Police, after hearings at the Rohini Court, said a senior police official.
They finally stopped at Bhagwan Mahavir Hospital, where two of the prisoners - identified as Paras Goldy (30) and Pradip Bhola (32) - were declared dead on arrival.
According to the police, the accused men first beat up Goldy and Bhola. They then strangled the duo and hit their faces on the walls and floor of the prison van. When the duo collapsed, the accused men continued kicking them until the van stopped at the hospital.
"A case of murder was registered at the Mongolpuri police station," said Sanjay Singh, Joint Commissioner of Police (North).