A year after the Samjhauta express blast that killed 68 people including 42 Pakistanis near Panipat, the perpetrators of ghastly attack are still at large even as investigators claim they have found "vital clues" and hope the culprits will not be able to avoid arrest for long.

"Various agencies including state level and Central ones are at work. This is not all that easy a task and takes time. We have got some clues and leads and hope the perpetrators cannot escape for long," Bharti Arora, member of the Special
Investigation Team constituted to probe the blasts, told PTI.

Two powerful explosions had ripped through two coaches of the Lahore-bound Samjhauta Express on the night of February 18 near Deewana railway station, about 15 km from industrial city of Panipat.

Sixty-eight passengers had died in the ensuing fire that engulfed the two bogies of the train and many of them were burnt beyond recognition.

Arora, who is SP of Government Railway Police in Ambala, said various agencies were questioning a lot of people across many states and they had got some "vital leads".

"We cannot disclose at this moment what those clues were," said Arora.

"As and when we have something concrete, we will let everybody know," said Arora.

The attack, which was widely condemned, occurred when two bombs exploded in different general compartments just after the train passed Diwana station.