The dejected family of Indian prisoner Sarabjit Singh, who was attacked in Kot Lakhpat Lahore jail last week returned to India via Wagah Border on Wednesday as the condition of the Indian prisoner remained highly critical amid reports that he is brain dead.

Sarabjit Singh was attack by two death row prisoners who apparently wanted to take revenge from the Indian prisoner who is also on a death row for carrying out terrorist activities in Pakistan.

A visibly distraught Sarabjit's sister Dalbir Kaur told newsmen at Wagah border that she was returning to India to take care of Sarabjit's children. She demanded that Pakistan should hold an inquiry as to how Sarabjit's security was compromised and he was subsequently attacked with bricks and iron rods.

"If the attack was planned by the government itself then there is no need for an inquiry. But if Sarabjit was attacked without the knowledge of the authorities then an inquiry is definitely needed."

Sarabjit's lawyer Awais Sheikh said he would file a fresh petition in Lahore High Court (LHC) seeking its permission to allow the Indian doctors to be part of the medical board which is treating Sarbjit Singh. Sarabjit remains in deep coma and doctors are not very hopeful about his survival.