Shibbir Ahmed, 22, who had been arrested from the capital's Sabujbagh area on Thursday, was a neo-JMB member and had connections with the international militants, said police sources.
He was engaged in militant activities of the neo-JMB – a branch of banned Jama'atul Mujahedeen Bangladesh (JMB) – from the very beginning of its formation and organised its media wing, sources also said.
Shibbir was a close associate of the deceased Neo-JMB chief, Maynul Islam Musa, believed to have been killed in a police operation at a militant hideout in Sylhet in 2017, said a press release on Friday.
Officials of the Counter Terrorism and Transnational Crime (CTTC) unit of Dhaka Metropolitan Police claimed the arrestee had plans to increase strength of the Neo-JMB and carry out destabilising activities through collecting funds from different foreign nationals.
The release said, after Musa's death, Shibbir detached himself from the organisation for a while but re-joined it through online in 2018.
He was trying to establish communications with IS-inspired militant groups in other countries using different online identities, said an official involved in the investigation.
Saiful Islam, deputy commissioner of the CTTC unit, said Shibbir managed to connect with some militant outfit members in the Philippines, Indonesia, the United Kingdom, France and Afghanistan, and also had financial transactions with some foreign nationals who had returned from Syria.
The police official further said they had received additional information from Shibbir after his arrest and were now verifying it.
During the arrest of Shibbir, the CTTC team seized a cell phone, five jihadist books and a bank deposit receipt from his possession.
Shibbir completed Dakhil from Bashabo's Saydia Dakhil Madrasa in 2017. He worked as an assistant imam at different mosques in Dhaka and operated militant activities under the guise of his profession, claimed CTTC officials.
A case has been filed with Sabujbagh Police Station against Shibbir.