Rab officials said they had general information from different sources that the militant kingpin was staying in a house in or around Shaplabagh in Sylhet City.

As this was further substantiated by information gleaned from Hafez Mahmud who was arrested in Dhaka on Tuesday, a Rab team from the headquarters rushed to Sylhet that afternoon.

However, the Rab did not have enough information to pinpoint Rahman's hideout. "So, we cordoned off an area of two-kilometre radius around Shaplabagh," a Rab official told The Daily Star.

As the Rab men started door-to-door search in Shaplabagh Tuesday night, residents of Surya Dighal Bari on Road No. 2 made no response despite repeated knocks.

"One of the residents rather reacted quite harshly inquiring our identity," said the Rab source. Learning that it was Rab, they said they would not open the door.

"The residents said they have bombs in their possession and threatened to blow up themselves, forbidding us not to try to enter the house," said the Rab official. "This made our suspicion even stronger that the militants are inside the house."

At one stage, Rahman started preaching the Rab men to follow the rules of Islam, calling them "kafir" (non-believer). "This intensified our suspicion more and we concentrated on the house and called in reinforcements," said the Rab official.

"We were finally convinced when his wife Ayesha Rahman Rupa came out yesterday noon and confirmed he was staying in the house," he added.

Rab Additional Director General Colonel Mahbub Alam Mollah, however, told The Daily Star over phone last night, "Although we had conversation with him and are convinced after talking to his wife, we are yet to see Rahman."

Another Rab official said, "We have taken enough caution so that Rahman cannot slip through our cordon, no matter which house he has been hiding in." Rahman refused to open the door for Rab as he realised he would not be able to escape, he said.

The Rab men have been working round the clock and no reinforcement was sent in until 12:30am today.

Earlier on January 19, the Rab cordoned off a five-kilometre area in Poradaha in Kushtia while raiding on information that Rahman and other top JMB leaders were holding a secret meeting at a rice mill there.