The bombs used in the Hyderabad twin blasts bear an uncanny similarity to IEDs used in previous attacks by the Indian Mujahideen,including the use of ammonium nitrate,an alarm clock and an old bicycle.
With Pakistan trying to distance itself from Indian terrorists following the 2001 attack on Indian Parliament,the supply of RDX that could be traced back to the neighbouring country dried up as did active operational support of the Harkat-ul-Jehad-e-Islami or Lashkar-e-Toiba. Need was felt to have a group of local operatives using IEDs made from sourced material at home leading to the emergence of the Indian Mujahideen.
In its attacks since,the IM has established its own signature involving use of e-mails,ammonium nitrate and watches of brand Samay. The detonators are sourced from either Andhra Pradesh Explosive Limited or Rajasthan Explosive and Chemical Limited,establishing the India link.
In February 2005,in the first known IM attack,IEDs were kept inside big milks cans and planted at a Varanasi ghat. One of the bombs exploded while the other did not. Atif Ameen would master the second bomb for the IM. Packed in a suitcase,it would be planted on the Patna-New Delhi Sharmjeevi Express at Varanasi in July 2005. Thirteen died in the attack. Ameen was killed in the 2008 Batla House encounter. The Delhi serial blasts of October 2005 followed. This time,the IM packed bombs in a pressure cooker and tiffin box and left them in crowded markets. All the bombs exploded,killing more than 60. The IM replicated the pressure cooker bombs in Varanasi in March 2006,targeting the Sankat Mochan temple,the railway station and a market nearby. One of them did not explode. In July 2006,seven similiar pressure cooker IEDs were planted on Mumbai local trains,killing more than 200. In 2007,the IM first used a bicycle,deploying it to carry out three blasts at Gorakhpur in May 2007. The IEDs used in the 2010 German bakery bomb in Pune were,however,kept in a bag.
Between 2005 and 2007,the shape of the container of the bomb kept changing. The now famous boat-shaped structure was first tried in the 2007 Hyderabad twin blasts and later used in the Jaipur,Ahmedabad,Surat and Delhi serial blasts of 2008. Out of the three bombs planted in Hyderabad in 2007,only two exploded. The group again used the boat-shaped structure in 2012 in Pune. While the shape of the bombs used in Thursdays blasts is not known so far,the IEDs were directional in nature,meant to cause maximum damage. No live IEDs have been found to corroborate this. Except in Surat,the module of Atif Ameen was used to carry out the attacks. The failed Surat bombings were carried out by the Pune module using EEPROM chips.
The group first experimented with Ajanta clocks,digital clocks and China watches,but when all of them failed,it turned to Samay. The presence of two detonators necessitates a battery with high voltage. In 2012,a digital watch was used for the first time by IM as a delay mechanism. The man behind the first set of timers used by the IM was Arif Badruddin,one of its founder members.