A team of investigators of the Tamil Nadu CB CID police, that had been camping in Bangalore over the past week to investigate the May 1 twin blasts on the Bangalore Guwahati Express at Chennai Central station, returned to Chennai Saturday with little by way of leads to crack the case.
A TCS techie from Andhra Pradesh going going home was killed in the blast.
The Tamil Nadu CB CID team is expected to return over the next week to question some of the persons arrested in prior terrorism-related cases in Karnataka in the hope of getting some leads.
The team, headed by two officers of the rank of Superintendents of Police, took extensive statements from train ticket examiners who were on board the fateful train till the Jolarpet station, all coolies, hawkers at the Bangalore city station and railway staff. The team also collected CCTV footage from in and around the stations that the train passed en route to Chennai.
“We gathered from talking to the passengers in the S4 bogie where the blast occurred and the TTEs that were onboard the train that there was continuous movement of passengers across the train during the journey. None of the injured could recall seeing anyone place a parcel below the seat where the explosion occurred,” sources from the team said.
One of the questions that investigators were wrestling with, sources said, was the intended target – the train, the Chennai station or any other particular place. Sources said one of the explosive devices had created a giant keyhole-shaped crater in the bottom of the bogie where the blast occurred, indicating that they could have been placed in a similar shaped metal container rather than a pipe bomb as it has been stated while comparing the blast to the Patna blasts of October 2013.
Questions have also been raised on whether the bomb maker was an amateur on account of the fact that a metal container was used to hold the bomb – thus reducing the total energy of the explosion and the velocity of the projectiles that were packed into the container. Sources said metal pieces and tiny remnants of the needle of a timer had been found. The kind of metal that contained the bomb – steel or aluminium – was also not clear, sources said.
Another issue that investigators were yet to obtain clarity on was the nature of the explosives used. Some officials of the CB CID reported the odd presence of ammonium nitrate and sulphur even as agencies like the NSG have reported ammonium nitrate and fuel oil. Investigation into the identities of passengers who boarded the train at Bangalore had not provided any leads, sources said.