On Thursday police had said firearms and a suicide vest had been found at the house in Trimohoni village.
Explosions and exchange of gunfire was reported from near the house after the start of the operation on Wednesday and continued into Thursday morning, said police.
Police have been unable to identify three of the four dead bodies found after the raid.
“The explosives found at the Chapainawabganj militant hideout look as if they have been brought in from abroad,” said Counter-terrorism Unit Chief Monirul Islam told a press conference on Saturday.
Operation Eagle Hunt was the most successful of the recent raids, the detective official. There were no casualties among the security forces and a woman and a child had been brought out from the hideout alive.
Two of the deceased committed suicide, believes Monirul. The other two may have been killed by police fire.
One of the deceased has been identified as local resident Rafiqul Alam Abu, hose wife Sumaiya and child were recovered alive.
Police believe one of the three remaining dead is neo-JMB leader Abdullah. Explosives had been recovered during a raid on Abdullah’s home in Jhenaidah on Apr 22.
Sumaiya revealed two of those killed had come from Jhenaidah during an interrogation, said Monirul.
He believes Abdullah and his companions had gone from Jhenaidah to the Chapainawabganj hideout with explosives.
The explosives at the Chapainawabganj hideout were kept ready for a future operation, said Monirul.
Four undetonated bombs, alongside a suicide vest, had been found, he said.
Spice vendor Abu, 30, had been converted to militancy by his wife, claimed Monirul.
Both Abu and his wife’s families were involved with Jamaat-e Islami, said Monirul.
Investigation into income sources
Police do not have a clear idea of how the militants were being financed.
“We are investigating their source of funds through Bangladesh Bank,” said Monirul.
“We have noticed the involvement some individuals and political parties, but we cannot speak of it yet. The matter must be considered on a case-to-case basis.”
Militants also raised funds by selling their possessions or by working, he said. Some with close ties to the organisation send funds from abroad.
India has long blamed Pakistan for producing huge quantities of counterfeit Indian currency as part of its economic warfare .
“We have received information about the involvement of various organisations from time to time. Several officials from embassies in Bangladesh have been withdrawn over this.”
Though Monirul did not name Pakistan, his suggestion was clear. A member of the country’s consulate in Bangladesh had been recalled after allegations of militant ties. Government ministers have also spoken of the country’s support for militancy.