Police in India say they have arrested the mastermind behind last month's bomb attacks in the holy city of Varanasi.
A wedding party bore the brunt of the temple blast
Vali Ullah, a resident of northern Uttar Pradesh state, ran a religious school and was associated with a famous seminary in the state, the police said.
Fifteen people were killed and over 100 others hurt in the twin blasts at a Hindu temple and a railway station.
The police said the blasts were conducted with the help of a Bangladesh-based extremist group.
Senior Uttar Pradesh police official Jag Mohan Yadav told reporters that Mr Ullah was arrested in Gosaiganj near the state capital, Lucknow.
"He was the mastermind of the whole operation which was conducted with the help of a Bangladesh-based group called Harkatul Jihadi Islami," Mr Yadav, who is inspector general of police, said.
No group has claimed responsibility for the attacks.
Senior Superintendent of Police SK Bhagat alleged that Bangladesh was being used as a transit route by militants.
"It appears that such groups are using Bangladesh as a route for infiltration since the route from Kashmir and Rajasthan is effectively sealed."
There was no immediate comment from the Bangladeshi authorities.
The police had earlier freed two men they arrested in connection with the blasts.
A wedding party took the brunt of the attack at Varanasi's famous Sankat Mochan temple.
Nine people died on the day of the temple attack and five at the city's Cantonment railway station. A child died two days later.
Varanasi, also known as Benares, is about 670 km (415 miles) south-east of Delhi.
It is the religious capital of Hinduism and is usually packed with Indian pilgrims and foreign tourists.