Police in the Indian capital Delhi say they have arrested the suspected co-ordinator and financier of last month's deadly bomb blasts in the city.
The bombs hit markets crammed with shoppers
Delhi police chief KK Paul named the man as Tariq Ahmed Dar, and said police were hunting for four accomplices.
He said Mr Dar, 33, was arrested in Indian-administered Kashmir and belonged to the outlawed Lashkar-e-Toiba militant group.
More than 60 people were killed and 210 injured in the 29 October blasts.
Mr Dar has not been formally charged but police have obtained court permission to detain him for two weeks for further investigation.
Police said Mr Dar was a science graduate and worked for a leading Indian pharmaceutical company.
He also wrote for a magazine in Indian-administered Kashmir, which discontinued publication in 2003.
Lashkar-e-Toiba is one of the main groups fighting Indian rule in Kashmir and is much feared.
Pakistan's President Pervez Musharraf banned the group in January 2002 amid pressure that followed the 11 September attacks in the US.
Earlier this month, the army had detained a man in Indian-administered Kashmir in connection with the blasts.
But the police said they had not found any evidence against the man after questioning him for two days.
The three blasts in the capital came within minutes of each other when many people were out shopping ahead of the Hindu festival of Diwali and the Muslim Eid celebration.
Two of the explosions ripped through the crowded Sarojini Nagar and Paharganj markets. A third exploded on a bus but killed no-one.
A previously little-known group called Inqilabi has said it carried out the attacks. Police have not verified the claim.
India has suggested "foreign" links, which analysts interpret as Pakistani militants. Islamabad says it has no such evidence.