The Uttar Pradesh police said Ghaus Mohammad Khan, who was an airman in the IAF for 15 years used his technical knowledge to assemble and supply arms and plan attacks, including the train bombing in Madhya Pradesh in which ten people were injured.

Khan, who the police now believe was the brain behind this module, is believed to have radicalised other members of the cell including Saifullah. The name of the second man arrested today, Azhar, was found in a diary recovered from Saifullah, police said.

Closed-circuit television footage from near the train explosion site helped the police identify the blast suspects. They tracked Saifullah to his hideout in Lucknow and tried to capture him alive, but he refused to surrender.

After he was shot dead, an ISIS flag and a train timetable were discovered near him. The police arrested five people on Tuesday.

Senior UP police officer Daljit Singh Chaudhary said there is no evidence that the suspects had any direct connection with the ISIS and appeared to be "self radicalised". He told reporters, "There is no evidence of any outside funding or any external support. They were self reliant."

Madhya Pradesh Home Minister Bhoopendra Singh Thakur, however, insisted that the suspects sent a video of the blast to a number in Syria over WhatsApp. Some officials in the National Investigation Agency (NIA) suggest there were signs of a handler that guided the suspects, most likely from outside India, through chat rooms and phone calls.

Home Minister Rajnath Singh made no mention of the ISIS when he spoke in Parliament today. He said by disowning Saifullah, his father has made an important statement. "I express sympathy for the father and I am sure the House joins me...the government is proud of Mohammed Sartaj and I am sure you are too," the minister said.

Sartaj Mohammad thanked the minister. "This message should be for the whole country. Ordinary people like us are being given respect by ministers," he said in Kanpur, Uttar Pradesh, where he lives.

The police recovered eight pistols and more than 600 rounds of ammunition, explosives, gold and passports from the house where Saifullah was shot dead on the outskirts of Lucknow.