"They met quickly and went to the parking. A man was wearing black clothes. They came here and put a black polythene in the dustbin and went away," 12-year-old Rahul said.
The boy claimed that the bearded men wore pyjama-kurta and left in an three-wheeler minutes before the blast.
He was picked up by police yesterday to get information about the tragic incidents.
On injured people, he said about six to seven persons were lying on the ground after being hurt in the blast.
The police arrived within six to seven minutes of the blast, he said.