Khan (32) had escaped from India to Nepal after the 2008 Batla House encounter and had settled in the Himalayan country. He was living the life of a school teacher there, a senior Delhi Police special cell officer said.
He had got the citizenship of Nepal through fake papers, he said.
There he married a Nepali Hindu woman who converted to Islam and assumed the name of Sara. The marriage happened four years ago, the officer said, adding that she was unaware of his involvements in terror activities.
"His wife did not know about his involvement with terror blasts and his work as an Indian Mujahideen (IM) terrorist. He had told her that there was a minor problem and he will deal with it," he said.
Khan was born in Uttar Pradesh's Azamgarh and studied there at different schools.
Initially, he and his elder brother Shariq Khan stayed with their uncle Dr Fakhre Alam and started studying at the Shibly National Nursery School from where he shifted to another school, the officer said.
He said that while living as a student in various localities in Azamgarh, Khan came in touch with radicals.
From April 2004 to May 2005, he stayed at his maternal uncle's house in Lajpat Nagar, Delhi. He took admission in B.Tech (Information Technology) at the SD College, Muzaffarnagar, where his elder brother was also studying, he said.
He however, failed in the second year of the course and dropped out.
After escaping from the Batla House encounter , he roamed around seeking shelter in Uttar Pradesh, Rajashtan and Maharashtra and most of his time was spent in buses and trains, the special cell officer said.
Later, he came in touch with a Nepali resident Nizam and with his help crossed the Indo-Nepal border from Bihar into the Himalayan country, he said.
He reached Birat Nagar and managed to procure a Nepali citizenship and passport.
He had stayed in Palpa, Kapilavastu and Gorkha area there. During his stay in Nepal, he initially ran a restaurant and later on started teaching in different schools, the officer said.