"He has not committed suicide. He has been murdered and then hanged. I am saying this on the basis of the fact that evidence has been erased. He could not move his hand as it was fractured," his father claimed.
He said there should be a CBI inquiry into the incident.
"I am also demanding that the post mortem be held in front of me," he said.
Asked whether there was any threat to his life, the father said Singh was beaten up inside jail.
He said his son had already admitted that he had committed a crime and that he himself had said that he should be punished.