According to details, the suspects were residing in a house closed to site of attack, who turned out not to be residents of Sindh, when questioned by the personnel.
The suspects when asked told that they were present at the house when the attack took place.
Moreover, intelligence officials whisked both of them away to an undisclosed location for further interrogation.
Our correspondent Kamil Arif told that the attack is being seen as part of a series of incidents which took place across the city in the recent past.
He said that various teams are probing the Karachi bus massacre and officials said that today’s attack has similarities with the bomb attack which targeted Bohri community in Aram Bagh area some time ago and the recent killing of two DSPs in the city.