Terror groups have resorted to “unique” innovations in fabrication of Improvised Explosive Devices (EIDs) by using household items. The techniques in fabrication of IEDs are also used for making other crude devices like improvised grenades and rockets. These devices are then connected with a clock to act as delay timers. Terror groups are blending chemicals used for manufacturing matchsticks with tapioca flour (sabudana atta) and filling small lPG cylinders with this mixture for maximum impact. Matchstick heads that contain potassium chlorate, sulphur and antimony sulphide act as the base explosives in such devices.
These new methods used by terrorists to fabricate the IEDs have been listed by the Intelligence Bureau (IB) that made a case study of the Burdwan blasts that took place on September 2 and 3, 2014 and Bijnor blasts that took place on September 12, 2014. The IB report has been circulated to various other security agencies for reference. “The accidental blasts and subsequent recoveries in Bijnor (Uttar Pradesh) and in Burdwan (West Bengal) are representative cases of innovative techniques being employed by terrorists in preparation of IEDs and crude devices like improvised rockets and grenades,” the IB said in its case study report.
The report further said the methodology adopted in these cases was unique and totally different from the one used in Bodh Gaya, Patna, Chennai and Pune blasts. An accidental low-intensity blast took place in a house in Jattan Mohalla on Chamunda Road in Bijnor. The explosive mixture included ingredients used for making matchstick heads. The terrorists used a 1 kg lPG cylinder filled with gas and inserted two wires with the filament of a decorative bulb along with the explosive mixture inside the cylinder through a hole made in its body that was sealed with a branded adhesive.
Other items seized from the Bijnor blast site included galvanized iron (GI) elbow pipe with cast iron caps, five cartons of matchboxes (each containing 600 matchboxes, one quartz clock modified as a timer, quite similar to the one used in Patna and Bodh Gaya blasts. “It appears that the terrorists were trying to crush the matchstick heads for putting the powder inside the lPG cylinder. The open end of the decorative lamp was supposed to be inserted in the cylinder, one end of the wire of the bulb was to be connected to a metal screw of the quartz clock and the other to the terminal of a battery. It would have triggered the explosive powder, thereby ripping apart the cylinder and the pipe,” the report said elaborating on the triggering mechanism used by the terror groups.
In the Burdwan blast case, a wired timer circuit without printed circuit board was used. The electronic timer circuit contained an integrated circuit, a condenser, a resistor with different coloured wires. A small size momentary switch (12 V/23A) and alkaline battery was used to operate the timer circuit. The circuits of the IEDs in Burdwan were designed for eight to eleven minutes delay and the grenades had short delay of four to seven seconds.
“This type of improvised electronic delay timer has been reported/observed to be used for the first time in the fabrication of hand grenades,” the report noted. An aluminium pipe was used in fabrication of a crude but effective detonator by filling one part of it with lead Azide and other part with Picric acid soaked on blotting paper. A single filament of decorative bulb was inserted to activate the detonator.
In some other types of IEDs, an explosive mixture of ammonium nitrate, potassium chlorate and aluminium powder packed inside GI pipe was used. In other IEDs, a mixture of gun powder, nitro cellulose and tapioca flour was used. likewise, the improvised grenades were fabricated using small section of GI pipes (using the kind of explosive mixture used in making IEDs) along with an actuating/striker mechanism using spring (from ladies’ hair clip). Similar methods were employed to fabricate the improvised rockets, a number of which were recovered from the Burdwan blasts site and related factories run by the Bangladesh-based Jamaat-ul Mujahideen, Bangladesh and its affiliates here.