Chennai/Bengaluru: The Tamil Nadu police have released CCTV footage of a possible suspect getting off the Guwahati-Bangalore Express on which two blasts early on Thursday morning at the Chennai railway station killed one and injured 14 others.

In the footage released by the Crime Branch of the Tamil Nadu police, the man is seen alighting from the train as soon as it entered the Chennai central station. The man is suspiciously seen running away in video captured by cameras at the station.

The mastermind behind the April 2013 Malleswaram blast – Abu Bakr Siddique alias Kakka – may be behind Thursday’s twin blasts in the Bengaluru-Guwahati Express at Chennai central railway station, that claimed the life of a 24-year-old techie P Swathi and injured 14 others.

Top official sources indicate that the modus operandi in both the terror attacks was similiar.

“They had made an improvised explosive device (IED) using ammonium nitrate with pellets in the Malleswaram blast. It was detonated with a timer device, which was buried in the explosives hence the police couldn’t detect the device because it had melted in the blast. In the train blast also, the terrorists have used ammonium nitrate mixed with pellets, some of which killed Swathi after they pierced her chest. The explosive was detonated using a timer device, which has not been found as yet. They may have imbedded the device in the explosives,” said an official source.

Read: NIA, NSG not to probe Chennai train blast

Key suspects in the Malleswaram blast, members of the banned Tamil Nadu based terror outfit – ‘Al Umma’, were arrested by the crime branch of Bengaluru police and Tamil Nadu police. However, Siddique continues to be at large. The terrorist is from Nagapatinam and has 7 cases under the Explosive Substances Act.

Siddique was trained to make explosives in Afghanistan and Pakistan. “Siddique fled the state in 1997 after being released from jail. He had reportedly taken refuge in Saudi Arabia. His whereabouts are not known, but he is said to be actively recruiting vulnerable youth in south India for jihadi activities,” the officer added.

Meanwhile, the crime branch of the criminal investigation department, Tamil Nadu, which is investigating the case, has reportedly got some concrete leads in the terror attack, said an officer on condition of anonymity.

But so far no terror organisation has claimed responsibility for the attack, he added.