Dalbir Kaur- sister of Sarabjit Singh who is currently in coma in a hospital in Lahore following a brutal assault- on Wednesday alleged that the Indian government had failed to protect his brother in Pakistan and demanded that he should be brought to India for treatment.Dalbir - who returned from Pakistan along with Sarabjit Singh's wife Sukhpreet and daughters Swapandeep and Poonam through the Wagah-Attari joint check post on the Indo-Pak international border - said that the government was aware of the threat to his life, but it did not initiate action to save him."I am disappointed," she said. Dalbir said that Prime Minister Manmohan should quit since he was unable to protect an Indian citizen. Sarabjit's family members had gone to Pakistan on Sunday.She however said that Sarabjit Singh's family would meet the the UPA chairperson and the Congress president Sonia Gandhi to "brief her about Sarabjit's condition." She would also request her to press the union government for asking Pakistan to handle the case in a sensitive manner.Sarabjit's daughter Swapandeep Kaur stated that they had met him five times. Her father did not realise that his family members were with him. "We want to bring him back to India," she said.Dalbir Kaur meanwhile alleged that attack on Sarabjit was planned."The jail authorities facilitated the entry of accused inside the prison. It was a pre-conceived conspiracy on the part of Pakistan jail authorities. The Indian government also betrayed us. I had repeatedly told the government that there was threat to his life in jail. I did not highlight the issue in the media hoping that the government would act and save Sarabjit.""Dr Manmohan Singh should resign immediately," Dalbir said. "He could not save an Indian citizen languishing in Pakistan jail."She said that there was movement in Sarabjit Singh's body. "His right eye and arm show the signs of movement. He is alive. But I suspect the authorities in Pakistan could harm Sarabjit. I want to meet the prime minister and seek his intervention to bring him to India for treatment. I suspect the doctors treating Sarabjit Singh in Pakistan," She said.She stated that the attack on her brother was linked to the hanging of Ajmal Kasab - a Pakistani militant affiliated to Lashkar-e-Toiba - who was captured alive in the 2008 terror attacks in Mumbai."We hanged (Ajmal) Kasab and they (prisoners) assaulted Sarabjit," she said.Dalbir Kaur said that she doubted medical treatment being given to Sarabjit in Pakistan. "I suspect the line of treatment is not correct. They attempted to mislead me. They felt offended when I sought explanation from the doctors on the line of treatment."She returned to India to take care of Sarabjit's children, she said."The Taliban has sent me a threat. I brought Sarabjit's children and wife back to India and I will return to Pakistan. Let them kill me," she said.She added that Pakistan should hold an inquiry to find out how Sarabjit's security was compromised and he was subsequently attacked with bricks and iron rods.Sarabjit's lawyer Awais Sheikh, meanwhile, said that he would move the Lahore High Court and file a petition for directions to the government for allowing the Indian doctors to be part of the medical board treating Sarabjit Singh. "He is in deep coma and I hope he survives," she said.Sarabjit was sentenced to death for alleged involvement in four bomb attacks in 1990 in Multan killing 14 people.In 2008, Pakistan President Pervez Musharraf had stayed Singh's execution following the intervention of human rights activists and appeals by his sister Dalbir Kaur. His fresh plea for mercy is pending before the president of Pakistan.