Police forensic teams are hunting for clues to who carried out twin bomb attacks that killed at least 42 people in the south Indian city of Hyderabad.

The explosions took place minutes apart at an open-air auditorium and a popular outdoor restaurant.
Investigators have been sifting through the wreckage looking for any leads.
Indian President Pratibha Patil said the attacks were aimed at disturbing harmony in the city which has a mixed Muslim and Hindu population.
Some 50 people were also injured in the incidents, in Andhra Pradesh state.
Andhra Pradesh chief minister Y S Rajasekhara Reddy described the blasts as a suspected ""terrorist act"".
Unconfirmed reports said police had defused a number of other explosive devices around the city.
------------------- Relatives await news
Hyderabad has been placed on alert, with extra police out on the streets.
The authorities want to keep a lid on any religious tensions, the BBC's Sanjoy Majumder, in Delhi, says.
The explosions came three months after 11 people were killed in a bombing at the city's 17th-Century Mecca Mosque. Police have yet to formally name suspects for that attack.
Meanwhile, officials have begun the process of handing over the bodies of those killed in Saturday's attacks to their relatives.
But with many bodies yet to be identified, many people spent the night outside the city's hospitals hoping for news.
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People in the area said a huge explosion was heard in Hyderabad's Lumbini Park, popular for its restaurants and amusements, just after 1930 (1400 GMT) on Saturday.
The blast happened in an open-air auditorium, which was packed with families, watching a laser light show.
""I saw chairs flying in the air along with bodies,"" Vineet, a young man who was at the show with some 200 other people, told Indian television.
A few minutes later and several miles away, there was another explosion at a crowded local restaurant popular with Hindus and Muslims.
In the aftermath, blood-covered tin plates and broken glasses littered the road outside, reports said.
India's Home Minister Shivraj Patil is due to visit the city on Sunday. (Source: BBC