The 3 puzzles in Delhi car blast: Where bomber Dr Umar built IED, how he triggered it and who guided him; may have assembled explosive near Sunehri Masjid

Investigators are focusing on where Dr. Umar Un Nabi assembled the IED used in the Red Fort suicide bombing, with a parking area near Sunehri Masjid being a strong possibility based on CCTV footage. The method of detonation and any handler communication are still under investigation, with analysis of digital records underway.