Chouhan has, during his interrogation, told the probe agency that he planted one of the bombs in the train to Pakistan. His claims are being verified.
On February 18, 2007, twin blasts ripped through two coaches of the Samjhauta Express near Panipat, when the bi-weekly train was heading from Delhi to Lahore in Pakistan. Most of the 68 people who died were Pakistanis.
The NIA has already chargesheeted six people in connection with the case including right-wing extremists Swami Aseemanand and Sadhvi Pragya Thakur. The four others have been charged for assisting Aseemanand; two of them, however, are yet to be located.
The NIA says that in its four years of inquiry, it has found that "the entire conspiracy was hatched between 2005 and 2007 by the accused Swami Aseemanand, Sunil Joshi (now dead) and his associates...at different places in Gujarat, M.P. and other places."
Aseemanand's confession that he was also involved in the bomb blasts at Malegaon in Maharashtra in 2006 and 2008, both of which targeted Muslims, linked him closely to Hindu terror group Abhinav Bharat which counts Sadhvi Pragya as one of its founder members.