Naidu's convoy did not use jammer

Also Read Blast handiwork of PW: AP govt Naidu to be shifted to Hyderabad

"Normally the chief minister's car follows the jammer vehicle, which disrupts all electronic signals. But on Wednesday, the jammer was not taken to Tirupati," official sources in Hyderabad said.

The chief minister's wife Bhuvaneswari travelled along the same road a few minutes before the blast.