Long before its Azamgarh module was busted, the Indian Mujahideen (IM) set up a back-up cell which would keep them in business: Darbhanga.
Like Azamgarh, the place met the two key conditions - Muslim numbers and religious atmosphere.
Over the last two years, 12 of the 13 IM men held for the attacks in Mumbai's Zaveri Bazar and Pune, are from Darbhanga. And the Darbhanga link is only too clear in the recent blasts in Hyderabad.
Already, the NIA has conducted raids in the region - in Samastipur to track Tehseen Akhtar, one of the bombers, and in Madhubani to track one Kamal alias Bilal.
"The IM used the Darbhanga module to resurface from Bihar, manning it initially with boys from Azamgarh," said an officer involved in the investigations. "It coordinates with the Bhatkal module in Karnataka."
The Darbhanga module, in fact, grew parallely with the group's most ambitious operation - BADR, the bombings in Bangalore, Ahmedabad, Delhi and Rajasthan (Jaipur). When Riyaz and Iqbal Bhatkal were managing the bombing operations, Yasin Bhatkal was setting up shop in Darbhanga.
He lived in the region for a year under an assumed identity - one doctor Imran, who specialised in Unani medicine.
"The profession was carefully chosen. It paved the path for some easy talent spotting in a region ...," said an expert in the state home ministry.
Gauhar Jamali, arrested for the Zaveri Bazar blasts, said "Dr Imran" would always steer discussions towards jihad. He got friendly with those who listened intently and then began indoctrinating them.
"Currently the focus is on finding the boys Yasin was in touch with and who have been missing for more than a year," said the officer investigating the module.