Around the time the police teams were busy looking for clues to the blast near IIT Gate, an unidentified person threw an object outside former Prime Minister Atal Bihari Vajpayee's residence. “There was information that two persons came on a bike near 6, Krishna Menon Marg, Vajpayee’s residence, threw the object and left. Later, there were also reports that somebody threw it from a car,” said a source.

Initially, the police suspected it was a transistor bomb.

A caller had informed them about the incident and police officers, along with a bomb squad, reached the spot around 10.50 am to defuse the “bomb”. According to sources, they found a transistor with some wires jutting out. Teams from the Tughlak Road police station tried to ascertain if there had been a blast or it was just smoke, as the caller said.

“It was a transistor, that too a damaged one, and somebody might have thrown it from his or her car. There may not have been any motive. But since it was a sensitive issue and it happened in Lutyen’s Zone, we did not want to take chances,” said a New Delhi district officer.

The police did not reportedly register any case, but tried to trace those who threw the object, which was later sent for forensic examination at the Central Forensic Sciences Laboratory.

“No interception was received about an attack on the BJP leader in that period. But leaders have always been on the hitlist of terrorists. Many terror groups have used these kinds of bombs in attacks earlier,” said a source. Special Cell officers also looked into the matter.

The incident was also discussed in the Home ministry recently and Delhi Police officers were asked about the status of the case.

However, according to sources, no case under the Explosives Act was registered.