Union home ministry sources said the Tamil Nadu did not appear to be treating the explosion as a terror attack and were also silent about an offer for joint probe of state police and a team of the National Investigation Agency (NIA).
"What to do when the state government is not treating it as a terror case as of now," a senior home ministry official said.
The home ministry officials still decided to send a team of forensic experts on Friday to ascertain the nature of the blasts as well as the triggering mechanism used to detonate the explosives.
A 24-year old woman techie was killed and 14 others injured when two bomb blasts rocked the Bangalore-Guwahati Express at the busy Central Railway station today, an act which was condemned by President Pranab Mukherjee, Prime Minister Manmohan Singh as well as Jayalalithaa.
The two low-intensity bombs that went off in quick succession in S4 and S5 coaches about ten minutes after the train chugged into the platform in the morning, triggered of chaotic scenes with panic stricken passengers running for safety.
The home ministry had earlier directed the National Investigation Agency, National Security Guard and forensic experts to get ready to go to Chennai. While the NIA team was supposed to go from Hyderabad, the NSG and forensic experts were being readied in New Delhi.
On record, home minister Sushilkumar Shinde said he has directed his officials to provide all assistance to the state government.
Union home secretary Anil Goswami also said that the central government was in regular touch with the Tamil Nadu government and was ready to provide it all possible help.
NSG's bomb data centre is mandated by to collect forensic evidence of all explosions in the country.
