[4][5] Bombs were set off in two carriages, both filled with passengers, just after the train passed Diwana near the Indian city of Panipat, 80 kilometres (50 mi) north of New Delhi.
Both the Indian and Pakistani governments condemned the attack, and officials on both sides speculated that the perpetrators intended to disrupt improving relations between the two nations, since the attack came just a day before Pakistani Foreign Minister Khurshid Mahmud Kasuri was to arrive in New Delhi to resume peace talks with Indian leaders.
[5] India's National Investigation Agency (NIA) charged eight people in the terrorist attack, including Swami Aseemanand, a Hindu cleric formerly affiliated with the Rashtriya Swayamsevak Sangh.
[17][better source needed] The later statements of Swami Aseemanand of Sunil Joshi telling him of involvement of his men in the blast had caused confusion for the investigators.
Given the nature of the transnational service and the ongoing violence in the region, the Samjhauta Express was always heavily guarded, as it was a high-risk target for terrorist attacks.
Weeks after the Indian Parliament terrorist attack on 13 December 2001, the train service was discontinued amid security concerns.
Just days before the attack, Pakistani Foreign Minister Khurshid Mahmud Kasuri announced that he was going to Delhi on 21 February 2007 to meet with Indian government officials to continue peace talks and to sign a nuclear risk reduction agreement.
[27][better source needed] Twin blasts shook two coaches of the Samjhauta Express travelling between India and Pakistan at around 23:53 IST (18:23 UTC) on Sunday, 18 February 2007, shortly after the train had passed through the railway station in the village of Diwana, near the Indian city of Panipat.
[28] One railway employee manning the level crossing at the time stated: It was about 11.52 when I showed the signal lantern to the Attari [Samjhauta] Express which was coming in very fast, probably at over 100 kilometers an hour (62.1 mph).
Pakistan's Foreign Office spokesperson, Tasneem Aslam, claimed that the father, Rana Shaukat Ali, was harassed by Indian intelligence agency personnel at the Safdarjung Hospital.
Later, Aslam told press correspondents that the "[C-130] aircraft was still at the airport" and that Mr. Ali had chosen to travel back to Pakistan via a land route.
[47] In January 2010, Pakistan Interior Minister Rehman Malik accused India of not pursuing the case seriously, and of refusing to divulge details about the role of Lieutenant Colonel Shrikant Purohit.
[48] In October 2010, an 806-page chargesheet prepared by the Rajasthan anti-terrorist squad revealed that the Samjhauta Express had been discussed as a potential target for an attack at a meeting of Hindutva bomb makers in February 2006; the group subsequently travelled to Indore.
[49] In April 2016, Director General of NIA requested the United States government to provide information on LeT Key financier Arif Qasmani.
The Union Law Minister Ravi Shankar Prasad hinted the UPA government had planted the angle of role of "Hindu terror" and questioned the suspect's release.
[52][better source needed] On 30 December 2010, National Investigation Agency claimed that they have solid evidence that Swami Aseemanand was the mastermind behind the blasts.
He had roped in Sandeep Dange, an engineering graduate, and Ramji Kalsangra, an electrician, to build the improvised explosive devices used in the blasts.
[55][better source needed] Later RSS sent a legal notice to CBI accusing it for deliberately leaking Swami Aseemanand's confession in media.
[56][57][better source needed] However, in late March 2011, Aseemanand came out and stated: "I have been pressurised mentally and physically by the investigating agencies to confess that I was behind these blasts.
[59] In November 2011, Indian High Courts issued a stay notice to the National Intelligence Agency on the point that Aseemanand was tortured and coerced in prison and on the allegations that the investigation agency itself was biased by its association to the United Progressive Alliance government[60][better source needed] In early 2012, commentators started questioning the "Hindu" angle to the terror attacks, noting both the existence of an equally plausible "Muslim" angle[61] and the near impossibility of proving any claims[62] Many initial reports suggested that the prime suspects in the bombing were the Islamic groups Lashkar-e-Toiba and Jaish-e-Mohammed, both of whom have been blamed for many high-profile bombings in the past.
[63] On 1 July 2009, the United States Treasury and UNSC placed sanctions on Lashkar-e-Toiba, and named Arif Qasmani as having played a role in the bombing.
[66][67] On 12 February 2012, the National Investigation Agency of India arrested a suspect identified as Kamal Chouhan, former RSS worker from the Indore district in Madhya Pradesh and conducted intense questioning.
Chouhan is believed to be a close aide of Ramji Kalsangra and Sandeep Dange, two key Indian suspects in the case on whom the agency has announced a cash reward of ₹ 1 million for information of their whereabouts.
[17][better source needed] Rediff carried a report in 2011 that the later statements by Aseemanand on Sunil Joshi telling him of his role in the blasts had caused confusion among NIA and both the testimonies were contrary to each other.
[19] Per a report by The Indian Express Razzaq who had been in prison since August 2005 after being deported from Iran, was interrogated after Safdar's narcoanalysis and brought Qasmani to the attention of Intelligence Bureau as a Lashkar financier.
Per diplomatic sources due to this a dossier was given with Qasmani's purported involvement to the United States which according to a note recording an informal meeting between the NIA probe team and FBI was the cause for sanctions by Treasury Department on him.
Indian Minister of Railways, Lalu Prasad Yadav, condemned the incident[71] and went on to say that the attack was "an attempt to derail the improving relationship between India and Pakistan.
[73] Indian journalist Siddharth Varadarajan argued that the peace process should stay on track and that any wavering would be tantamount to surrendering to terrorism.
[74] The government of Pakistan reacted in the same vein, through its Foreign Minister Khurshid Mahmud Kasuri, proclaiming that this was an act of terrorism that should be investigated by Indian authorities.
"[75] In response to the terrorist attack, President Pervez Musharraf stated "such wanton acts of terrorism will only serve to further strengthen our resolve to attain the mutually desired objective of sustainable peace between the two countries.