The second round of questioning of Syed Naimath Ullah Hussaini, 42, Muzaffar Hussain Rizwan, 29, Mohammed Ataullah Rehman, 30, Abdul, 32, A.M. Azhar, 20, and Mohammed Arbaz Ahmed, 21 took place at an undisclosed location in Hyderabad.
The National Investigation Agency had questioned them for over 12 hours on Wednesday, after picking them along with five other suspects in an early morning raid at 10 locations in Hyderabad.
An NIA official said the six suspects had been released Wednesday night but were called in again on Thursday to face fresh questions.
The other five — Mohammed, 24, his brother Mohammed Ibrahim, 29, Habib Mohammed, 32, Mohammed Irfan alias Yaqais, 26, and Abdullah Bin Ahmed Al Amoodi alias Fahad, 30 — were arrested after day-long questioning.
The official said the five who have been arrested will be presented before a Special NIA Court on Thursday.
All the suspects — aged between 20 and 42 — were allegedly plotting bomb attacks and indiscriminate firing at shopping malls and crowded places in Hyderabad, NIA sources had said.
The NIA had recovered several arms, explosives and other materials used to manufacture Improvised Explosive Devises (IEDs) from the suspects.