A blast in a car near the Red Fort in Delhi on the evening of 10 November, 2015, claimed at least 12 lives and injured many others. At least eight people, including three doctors, have been arrested in connection with the case so far. But several unanswered questions remain.

Dr Umar Nabi, a resident of Jammu and Kashmir's Pulwama and a faculty member at the Al-Falah Medical College in Faridabad, Haryana, is suspected to be driving the white Hyundai i20 car that went off just 300 meters from the Red Fort.

Nabi has emerged as a key figure in what investigators are calling a "white collar terror network" spanning Jammu and Kashmir, Haryana, Uttar Pradesh and Delhi. It all started several days ago when the J&K police started a probe on posters that appeared in Srinagar in support of Pakistan-based terror outfit Jaish-e-Mohammad.

The chain of events leads back to Jammu and Kashmir via Faridabad and Turkey...

Reporters: Debayan Dutta, Aparna Singh
Video Producer: Shohini Bose
Video Editor: Rajbir Singh