In Ghansoli village of Navi Mumbai, an hour’s train-ride from Mumbai, Mumtaz Khan’s closest acquaintances, who work in a garment factory, describe him as a loner.

All they know about him, they say, is that Mumtaz—arrested for his alleged role in the serial train blasts—offered Urdu tuition in the area to earn a living and slept in the factory’s quarters in the night.

“He would often leave home at 7 am and return only around 11 pm. We don’t know where he went,’’ said Mohammed Illyas, who owns the factory that makes garments for dolls. ‘‘But on Wednesday (July 19) he didn’t come back. We had last seen him the previous night.’’

Mumtaz’s brother Nisar and younger brother Ansar live in Ganesh Nagar, a slum settlement.

“I just got a call from home that Mumtaz has been arrested,’’ Nisar told the The Indian Express. “I don’t know why, I don’t know where to go. I don’t know how my brother came into contact with such people.’’

Home for the brothers, said Nisar, is in Taimarehmat Village in Basti district, Uttar Pradesh. Mumtaz’s wife, five daughters and a son live there. Kamal Ahmed Ansari, arrested from Bihar, is Mumtaz’s brother-in-law, said Nisar.