Amritsar: The body of Indian prisoner Kirpal Singh, who died under suspicious circumstances in a Lahore jail last week, arrived in India on Tuesday. His family members alleged that his body bore injury marks and foul play led to his death, but doctors who conducted an autopsy denied this. Alleging foul play in his death, Kirpal's family members said the body bore injury and blood marks. Contrary to the claims, the medical board which conducted the post-mortem examination here after his body was brought back to India on Tuesday, said there were no external or internal injury marks on the body. Ashok Sharma, head of the three-member medical board, however, told the media after the post-mortem examination that the cause of death has not been established yet. The doctor said some organs from his body were missing, as an autopsy has already been done (in Pakistan). "In the post-mortem examination, it was found that there was no external or internal injury on the body. Post-mortem of this body has already been done (in Pakistan) because stitches were present on the body and the head. "When we opened the body, we found that some of the organs were missing because when post-mortem is done, some organs are taken to test to find out whether there is any disease or not," Sharma said. "... rest of the organs which were present, we took out portions of those organs and we sent them for testing (to know) about diseases as well as poisoning. I can say with 100 percent accuracy that the wound marks which are inflicted during life, they cannot be removed. The cause of death has not been established yet," the doctor added. After being handed over to the Border Security Force at the Attari-Wagah joint check post, Kirpal's body was immediately taken for post-mortem examination in Amritsar after which it was taken to Gurdaspur district for cremation in his native village. His family members alleged that he was murdered either by fellow prisoners or prison officials in Pakistan. Close relatives and residents from Kirpal Singh's village were present at Attari, 30 km from here, when the body was brought back to India. The body, in a coffin, was carried by porters on the Indian side even as family members showered flowers on the coffin. Close family members were allowed to see the body to identify Kirpal Singh's mortal remains. Pakistani authorities have attributed his death to heart attack, but his family has alleged he was murdered in prison. "He has been murdered by the Pakistanis under a conspiracy. He was the sole witness to the murder of Sarabjit Singh in the Lahore prison. We want a thorough inquiry and post-mortem to know the truth of his death," Kirpal's nephew told the media outside the hospital mortuary. Kirpal Singh, the family has maintained, had inadvertently crossed into Pakistan and was arrested and charged with spying by Pakistani authorities. His family had met union home minister Rajnath Singh and Delhi Chief Minister Arvind Kejriwal in New Delhi last week to seek immediate repatriation of his body to India. The Punjab government has offered to extend all help and relief to Kirpal's family on the same lines as given to another Indian prisoner, Sarabjit Singh, who was murdered in the same prison in Lahore in April 2013. Kirpal Singh, a former serviceman, was lodged in Lahore's Kot Lakhpat prison since 1992. He died on April 11. Pakistani authorities had labelled him a spy and got him convicted for terror attacks inside Pakistan. He was initially sentenced to death which was later converted to 20 years' imprisonment.