Police is yet to make any headway in the investigations in the Mehrauli blast despite questioning several people, including illegal Bangladeshi migrants.
The 'whodunnit' question has been hounding investigators from the beginning as the blast in a flower market in Mehrauli in south Delhi on September 27, came exactly two weeks after the serial blasts in New Delhi.
The bomb, which was dropped in the market by two motorcyclists, who masked themselves with helmets, also did not have 'signature components' of the explosives used by suspected Indian Mujahideen terrorists.
Three persons were killed and 21 were injured in the blast.
Suspicion fell on Bangladeshi nationals and local criminal gangs as there were at least three mysterious blasts in south Delhi this year. Two Bangladeshis were also arrested in this connection earlier.
"We have questioned several people. The investigations are still on. We are confident that we will crack the case soon," a senior police official said.
Similar modus operandi was used in Maharashtra and Gujarat, where bombs were placed by motorcycle-borne men to trigger blasts three days after the Mehrauli explosion.
"We are interacting with our counterparts in both states," the official said.
Police suspect that the aim of those behind the blast in Mehrauli was to create tension in the area during the fasting month of Ramzan and approaching Dussehra.
"It might be the handiwork of a fanatic group or that of a criminal gang who illegally migrated from Bangladesh. We are looking into it," the official said.
In search of clues, Delhi Police had sent teams to Aligarh in Uttar Pradesh, where local gangs are involved in making crude bombs, and New Jalpaiguri in West Bengal from where the two Bangladeshis were arrested.
Ruling out the involvement of Indian Mujahideen in the incident, another official said the chances of the outfit's involvement was 'very low' as the bomb used was 'crude'.
"It was loosely packed and so the intensity was low and look at the manner in which they planted the bomb. The timing of the blast also suggests that it is not likely to be carried out by Indian Mujahideen.
"Interrogation of those arrested has revealed that they selected evenings and crowded market places for maximum impact," the official said.
