The Delhi High Court blast was carried out using ammonium nitrate and other chemicals, according to sources in Delhi police.
The remains of the blast has been carried off for forensic examination yesterday.
Sources said the bomb was designed for maximum impact and nails and bolts were packed inside the package for creating maximum injury.
There was also a detonator attached to the package to set it off at the calculated time.
Eye-witnesses had said that the explosion threw red coloured powder as well as some “foam” all around the spot, raising the prospect that the explosive may be the same as was used in the Mehrauli blast in Delhi.
On Wednesday, a crude bomb exploded in the parking lot of the Delhi High Court, without causing any casualties, but damaging a nearby car.