Delhi Police on Sunday conducted searches across the city to nab the two-motorcycle borne youths, a day after they dropped a polythene bag with a bomb in it at the Mehrauli flower market killing three persons and leaving 22 injured.
The two men, believed to be aged around 30-32 years, riding a black motorcycle with Delhi registration number were responsible for the explosion.
Considering that Mehrauli is located on the border with Haryana, checking of vehicles has been intensified at the Delhi-Gurgaon border.
"We have questioned some people," a senior police officer said.
Police suspect that the aim of the those behind the blasts was to create tension in the locality as Ramzan and Dusshera are approaching.
The two well-built suspects were wearing helmets and black jeans and black T-shirts when they carried out the blast.
Investigators are suspecting the hands of illegal Bangladeshi migrants in yesterday's blast, saying the explosion does not have the signature of Indian Mujahideen, which carried out the serial blasts in Delhi and other cities.
They are also looking into the "continuity factor" of the blast as south Delhi has witnessed at least five similar low-intensity blasts this year.