Car bomb had ammonium nitrate with clock timer: Officials

The IM usually has its bombs in C-shaped open wooden boxes,with holes on the side for wires. The explosive is essentially tightly packed ammonium nitrate,held together by oil or nitrogen gel,metal balls and nuts,said officials,adding that an alarm clock is used as timer.

Forensic reports of the 2007 blasts in Uttar Pradesh courts,the 2008 blasts in Jaipur,Bangalore,Ahmedabad and Delhi and this years German bakery blast in Pune have confirmed that IM used ammonium nitrate with pellets and ball bearings tied with wires and clock timers.

According to the reports in these blasts,some RDX traces were found in only Delhi and Ahmedabad serial blasts. Same pattern has been used in Jama Masjid car blast but the idea of causing damage was not with pellets and ball bearings,but by causing fire in a transformer close to which car was parked, said an official.

The bombs made using ammonium nitrate,wires and clock timers could be assembled in very quick time and causes damage equal to what a bomb made of RDX causes, said an expert.

Explaining the modus operandi in planting the car in Jama Masjid,an official said,The car was parked there probably three to four hours before the explosion and it was done in a hurry.