Hyderabad: The hand of Pakistan-based terror outfit Lashkar-e-Taiba in the Hyderabad blasts is being probed by the National Investigation Agency (NIA) with media reports saying the premier terrorism investigating body of India likely to question LeT suspects who were chargesheeted earlier in Bangalore in other cases.
A BJP leader of Andhra Pradesh meanwhile claimed he received a letter from LeT and handed it over to the police.
Bharatiya Janata Party (BJP) Andhra Pradesh chief G. Kishan Reddy said he received a letter from LeT claiming responsibility for the bombings and warning of more attacks.
Reddy handed over the letter to cops in Hyderabad, said a TV report.
NDTV reports said the letter threatened a strike next in the city's Begum Bazaar area. Police confirmed media about the letter being received from Reddy.
The possible of role Indian Mujahideen (IM) in the attack has not yet been established while probe is on.
Prime Minister Manmohan Singh on Sunday visited the Hyderabad twin blasts site and met with some of the victims in two hospitals assuring them of all assistance.
On reaching Hyderabad on a special flight, he along with Chief Minister Kiran Kumar Reddy visited the blast sites at Dilsukhnagar and spent some minutes there and heard from the cops the progress in the probe.
At least 16 died and over 100 were injured in the twin blasts that ripped through a crowded area on Thursday evening.
On Saturday, six people have been 'detained' over the bomb attacks.
Several people have been questioned in connection with the strike, police said adding that no arrests were made so far.
Footage from CCTV security cameras is being scrutinised to identify suspects.
Earlier, Hyderabad Police Commissioner Anurag Sharma said that the police had done everything it could to prevent the terror strike in the city.
Speaking at a press conference, the commissioner also claimed that the police had received "vital clues" and was hoping to crack the case soon.
Six specialized teams have been formed and they have already started to collect evidences.
"SIT (special investigation team) will probe the blasts case. The city has been put on high alert," he said.
The commissioner added that the Andhra Pradesh government has announced a reward of Rs 10 lakh for credible information leading to cracking of the case.
"We are still not sure of the involvement of banned Indian Mujahideen (IM) in the case," Sharma said, adding that many clues were found in the last 24 hours.
The PM had earlier called the attack 'dastardly' and added that none of the guilty will be spared.
The PM had also directed the central agencies to extend all possible help to the Andhra Pradesh state authorities in relief operations.