Delhi blast: How much explosive was used?

Initial reports would suggest that the bomb used in Wednesday's blast at the Delhi high court had ammonium nitrate, but this was a professional job, reports Vicky Nanjappa

Forensic experts say that if at all it is ascertained that ammonium nitrate was used in this attack, then one could say that the bomb was made by a professional.

The first leads go on to indicate that the explosives were being carried in a suitcase. The question is, how much explosive could have been carried in a suitcase.

"For a blast of this nature, at least half a kilogram of ammonium nitrate would have been needed and this was the quantity that could have been inside the suitcase. Moreover, they would have had to keep the quantity down and going by the impact it gives the impression that the packaging was very good," says an expert.

All that is required is that it should be packed tightly, with a timer device attached to it. Further, when one looks at the impact that the bomb has created (a four-feet crater), one gets the feeling that it was RDX.

Also read: Explosive PETN used in Delhi HC blast 

However, the bigger question is, whether terror groups were ready to risk using RDX, considering the kind of scrutiny it attracts. Terror groups have virtually stopped using RDX in cities since it tends to increase the heat on them.

They have been using ammonium nitrate a great deal, thanks to the lack of regulation and the easy availability of the material.

"When one uses ammonium nitrate in a blast, the impact largely depends on the steel container or the pipe in which it is concealed. If this blast could create a crater of four feet, then the packaging was exceptional," says the expert.

"It looks like a bigger operation than just trying to kill and injure people. They had planted it in the car park and ensured that it had a big impact so that the vehicles could catch fire and create more chaos. Hence the impact was not meant to be wide as was in the 13/7 case," the expert added.

If it is ascertained that the bomb had ammonium nitrate in it, then it would be interesting to draw a comparison to the 13/7 blasts.

In that case the bomb was packed in a steel container. It was a very loosely-packed bomb and kept in an open place, so the impact was lower. When bombs are placed in an open area, it is designed in such a way that it creates a wider impact.

This would mean that the shrapnel that is packed with the explosive needs to fly a distance so that it can hit as many people as possible.

However, in the Delhi blast it appears that the bomb was packed in such a way to create an impact in close quarters and in order to make a powerful bomb, it is likely that the material was packed in steel pipes, which makes the impact stronger.

The Central Forensic Science Laboratory team which is looking into the bomb composition will have to ascertain the packaging of the bomb, apart from the material used. They would look into the metallic pieces that have been used in the making of this bomb.