Mohammed Akbar Ismail Chaudhary, who was recently arrested, had rented a bungalow in the upscale Habshiguda area of Hyderabad almost a month prior to the serial blasts on August 25 last year, police said.
"He and Anique Shafique Shaikh rented the bungalow where they stayed for almost a month and surveyed crowded spots in the city where blasts could be carried out," a senior police official from the crime branch said.
Chaudhary also received the delivery of explosives which is suspected to have brought from Mangalore, he said.
"About two days prior to the blasts Riyaz Bhatkal alias Roshan Khan arrived in Hyderabad," the official said.
Using timers allegedly sent by Mohammed Arif Shaikh, the arrested bomb maker, the trio assembled the bombs and on August 25 placed them at three locations in the city, he said.
The bomb allegedly planted by Chaudhary failed to explode while the other bombs planted at Gokul Chaat by Bhatkal and at Lumbini Park by Anique exploded, the official said.
A team from Hyderabad police was in the city for questioning Anique and Chaudhary on the matter, Joint Commissioner of Police (Crime) Rakesh Maria said.