Friday, May 27 2005 08:35 Hrs (IST) - World Time -

New Delhi: Even four days after the twin blasts in the national capital, Delhi Police continued to grope in the dark for clues.

While the blasts were believed to have been caused by plastic explosives, their exact nature remains unclear.

Police hopes to get some concrete idea about the explosives when the reports from Central Forensic Sciences Laboratory (CFSL) and the National Security Guards come in within a day or two.

Though preliminary probe did not reveal the "signature" of any particular group, identification of the particular kind of explosive used is likely to pinpoint the search to some outfit based on their preference for such material, police sources said.

Investigators suspect the involvement of some Khalistani extremist group, though they did not rule out the handiwork of Kashmiri or Pakistani militants.

On the basis of the strength of the explosives used, investigators were fairly certain that they were not meant to scare but to kill. At least one person was killed and over 55 injured in two explosions at two cinema halls in New Delhi on Sunday (May 22, 2005) when the controversial movie 'Jo Bole So Nihal' was being screened.

Police say it was providential that the row in Liberty hall where the bomb was placed was empty otherwise the number of casualties would have been far higher.

About a dozen people were still in hospital even four days after the incident, three in critical condition.