A highly volatile explosive called triacetone triperoxide (TATP), or even a mixture of ammonium nitrate and TATP, may have been used in the Red Fort car blast, sources in the National Investigation Agency (NIA) said on Sunday.
Investigators have also recovered three 9mm cartridges used by security forces from the spot where the Hyundai i20 exploded, leaving 13 people dead. Two of the cartridges are said to be live rounds while the third is an empty shell. Their recovery is surprising considering no pistol or weapon was found at the site.
“Forensic experts believe the explosion was triggered by high-grade material. Initial findings of the forensic science laboratory suggest explosives used in the car blast could be the extremely volatile triacetone triperoxide or a mixture of both ammonium nitrate and TATP,” said a security official attached to the Union home ministry.
The forensic team collected over 40 pieces of evidence, including residue from the explosive and the cartridges from the spot.
“Preliminary analysis of the explosives suggests that a large amount of ammonium nitrate was stored inside the car. Forensic experts also suspect the use of TATP in the blast. TATP can explode from heat without any detonator and is known for its powerful shockwaves. The residue is being examined to understand what led to an explosion of such a magnitude,” the official said.
Sources in the NIA, which probes terror cases, said there was still no clarity on whether it was a deliberately triggered explosion or an accidental blast as explosives were being transported for a larger terror strike.
“The recovery of the 9mm cartridges has added a new mystery to the ongoing probe. These cartridges are exclusively used by security forces or those with special permission. It is still unclear how these cartridges reached the spot or whether the alleged suicide bomber (Dr Umar un Nabi) had them in his possession,” said an NIA official.
Investigators, he said, are reviewing the digital trails, movement logs and communication history to map Umar’s activities before the blast.
Security agencies have so far not made any official announcement about who they believe to have orchestrated the terror attack.
Unofficially, however, investigators have said the probe points to the proscribed Pakistan-based Jaish-e-Mohammed (JeM).
Umar, who was driving the car, was part of “an interstate and transnational terror module involving white-collar, radicalised professionals and students in contact with foreign handlers operating from Pakistan and other countries”, an NIA official said.
The “white-collar” terror module came under the scanner last month after posters promoting JeM appeared in Srinagar.
Hours before the Red Fort blast, security agencies had busted the module linked with the JeM and the Ansar Ghazwat-ul-Hind, with operations spanning Kashmir, Haryana and Uttar Pradesh.
Among the arrested was Dr Muzammil Ahmad Ganai, who was picked up from Faridabad, and Dr Adeel Ahmad Rather, who was arrested from Saharanpur in Uttar Pradesh. Another doctor, Shaheen Sayeed, was taken into custody following the recovery of nearly 3,000kg of bomb-making material, suspected to be ammonium nitrate, from two rooms rented by Muzammil outside the Al Falah University campus in Faridabad.
Barring Adeel, all the doctors linked to the terror attack were employed by the university.
Sources said the suspects were allegedly preparing to execute coordinated explosions at several places in Delhi.