The first concrete evidence to the nature of the low-intensity improved explosive devices used in the nine blasts across Bangalore on Friday afternoon emerged with the discovery of an unexploded bomb on the pavement outside a mall in south Bangalore — barely 1 km away from the site where the lone death occurred.

The unexploded bomb, defused by experts from the National Security Guard and a bomb squad, was encased in a small bucket-shaped cement container and contained ammonium nitrate and fuel oil as the explosive material, senior police officials said.

From the outside, the device would look like an inverted bucket shaped cement block on account of a smooth cement finish at the top. Pre-cast cement, embedded with nuts and bolts acted as the missile material contained for the bomb and a micro-chip acted as a timer, a senior police official said.

From an analysis of the bomb sites and forensic evidence, police have summarised that all devices were made under common supervision. Karnataka director general of police R Srikumar described the bombs as being “professionally assembled”.

“Only at two bomb sites — Adugodi and the Vittal Mallya road circle - tiffin-box encasings for the devices were found. At all other places, including the unexploded bomb, found near the Big Bazaar on Saturday had plastic casings,” sources said.

Police have found leads to show that the bombs were assembled in Bangalore itself. Giving credence to this theory is the finding of local English newspapers in the packing of the bombs. One of the latest newspapers bears the date of June 27, another dates back to March, sources involved with the probe stated.

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