The Tamil Nadu special investigative wing probing the twin bomb blasts on the Bangalore-Guwahati Express suspect that the explosives could have been planted at Bangalore.

Sources in the investigation agency, which rushed a team to Bangalore to pursue the new leads it stumbled on has information that the perpetrators of the explosion could have got support from sleeper modules working in Karnataka.

An official refusing to be named told PTI here that information so far collated by it suggest that the bomb fitted with a timer devise could have been planted at Bangalore.

The CB-CID police have been interacting with neighbouring state police and viewing CCTV footages of Chennai Central Railway station, the scene of the blast, sources said.

"We are studying the footages to see if the accused actually travelled in the train", the official said.

The train, which left Bangalore on April 30 at about 1135 hrs, arrived here yesterday by 7.10 AM and was delayed by about an hour. Ten minutes after its arrival, two low-intensity bombs exploded in quick succession, killing a woman techie and injuring 14 others.

In another development a six-member NSG team led by Lt. Col. Balakrishna arrived here late last night to assist the state police in the ongoing investigation into the explosions, sources said.

The NSG team held discussions with top police officials of the state on the incident, the sources said.