NEW DELHI - In April 1992, Dr Khalil Chishti, a virologist from Karachi visited his ailing mother in Ajmer. Dr Chishti did not know that he would not return home to Pakistan for the next two decades, reported NDTV.On that visit to the city of his birth, the Pakistani scientist got caught in a brawl between two sets of relatives; one person was shot dead. Dr Chishti was arrested, though he protested all through that he was but an onlooker. The trial took 18 years; in 2010 he was awarded life-imprisonment for murder. An appeal in the High Court was rejected. In all that time, while he did get bail, his passport was impounded and he had to stay in Ajmer. For long years, Dr Chishti lived alone in his ancestral home in Hatundi near Ajmer, growing older and frail.Two decades is a long time. Back home in Pakistan, his daughters got married and he had grandchildren. His family has been quoted as saying that Dr Chishti even tried to set up a virology centre in Ajmer but was denied permission. A scientist who had taught in universities in Europe, Africa and Pakistan, had nothing to do but wait for a verdict.Last year his wife Begum Mehrun Nisa, in her 70s, daughter Shua Jawaid and grandson Ali Ghalib travelled to India to appeal that Dr Chishti be released. The octogenarian has had two heart attacks and as he fractured his hip bone two years ago, he now can't walk unaided and even for his basic ablutions he needs support and help from other people who carry him inside the jail. He has been in jail since his sentencing in 2010.Sources said Dr Chishti 's case was discussed at the lunch meeting between Prime Minister Manmohan Singh and Pakistan President Asif Ali Zardari during the latter's one-day India visit on Sunday. Pakistani officials have urged India to set Dr Chishti free, sources said. President Zardari's was on a private visit to the Ajmer shrine, with a diplomatic stopover in New Delhi. In June last year, Supreme Court Justice Markandeya Katju had requested Prime Minister Manmohan Singh to release Dr Chishti on humanitarian grounds. Acting on Justice Katju's appeal, Rajasthan Chief Minister Ashok Gehlot approved his mercy plea and sent it to Governor Shivraj Patil for final clearance. But Mr Patil sent a questionnaire to the law department on various issues related to the case and the mercy petition has remained pending in the Governor's office.Human rights activists have also sought Dr Chishti 's release for years. On Monday, the Supreme Court granted Dr Chishti bail but asked him to stay in Ajmer. It did, however, say that it would hear a fresh appeal from him to return to his country.