Official sources said 30 to 40 people have been interrogated by sleuths of Andhra Pradesh Police, National Investigation Agency and other central security agencies in connection with the Thursday's blasts which claimed 16 lives and injured over 100.
Investigators are also verifying reports that five people, who checked into a lodge at Dilsukhnagar, left just before the blasts or immediately after the explosions.
Out of the five people, two have turned out to be innocent. One had checked into the hotel under a fake name. He had checked out a few minutes before the blasts which led to the police to term him as a suspect, the sources said.
However, verification of three other persons, who had left the hotel around the time of the explosions, was still on, sources said.
Meanwhile, Union Minister of State for Home R P N Singh said all evidence collected from the ground have been sent for forensic examination and nodal agencies were looking into them.
"Whatever evidence the agencies have been collected, all have been sent for forensic examination. There are leads and we are looking into the leads," he told reporters here.