The death toll in Tuesday's bomb attacks on trains in Mumbai, formerly Bombay, has risen to nearly 200, and police have detained hundreds of people for questioning. India's Anti-Terror Squad released the names and pictures of two suspects.
One of the suspects is thought to be linked to the militant organization Lashkar-e-Taiba, but the group has denied involvement. Lashkar-e-Taiba, a Pakistan-supported group based in Kashmir, has been blamed for previous similar attacks.
In recent years, the group has also been connected to Students Islamic Movement of India (SIMI), which is believed to have deep roots in Maharashtra, the district containing Mumbai. Lashkar is known to have used SIMI activists to help carry out attacks. SIMI activists have been blamed for small train bombings in northern Uttar Pradesh in recent years.
Melissa Block talks with Somini Sengupta, South Asia bureau chief for The New York Times, about the ongoing investigation.