Remote bombs raise fresh militant threat

Counterterrorism authorities are investigating a potentially significant shift in militant bomb-making after two pressure-cooker bombs recovered near Dhaka were found to have been designed for remote detonation, raising fresh concerns over the possible revival of an organised explosives network.

The development has intensified a police manhunt for Nazmul Hasan, known as “Bomber Mamun”, a fugitive militant whom investigators suspect may have been involved in several recent bomb incidents in and around the capital.

The latest concern emerged after Counter Terrorism and Transnational Crime (CTTC) officers recovered bomb-making materials, detonators, electrical wires, remotes and controllers from a rented house in Shyampur, Savar.

The raid followed the arrest of Mamun’s alleged associate, Arif alias Imran.

Police say the recovered materials could help determine whether a militant network has begun using remotely controlled devices more systematically.

One of the clearest indications came from a pressure-cooker bomb thrown at a tea shop in Ashulia’s Charabagh. The device was found inside a travel bag along with a remote control, according to a CTTC official.

The official said the remote appeared similar to devices used to operate motorcycle electric locks and could have been used to trigger the bomb.

Days later, another pressure-cooker bomb was discovered in a field near Laltek Ghodra Mosque in Savar. CTTC officials said the device was also remotely controlled, although its remote was not recovered.

Police suspect the remote may have been left behind after those who placed the bomb abandoned it during a raid on Arif’s hideout. Both devices were later neutralised by CTTC bomb-disposal teams.

The developments have brought renewed attention to Mamun, whom police describe as an experienced bomb-maker with links to neo-Jama’atul Mujahideen Bangladesh, or neo-JMB.

Investigators say Mamun learned bomb-making from senior members of the militant organisation more than a decade ago. Police identified Mahfuz alias Shobuj Pakhi, who was killed during a police operation in Moulvibazar in 2017, as one of his mentors. Another prominent bomb-maker, Egyptian national Ibrahim alias Khabbab al-Mishri, was also killed during the security crackdown on neo-JMB.

Mamun survived the crackdown and was arrested in connection with the 2017 Hotel Olio incident in Dhaka. Police accused him of making the pressure-cooker bombs used in the attack, in which a suspected suicide bomber was killed.

According to investigators, Mamun later described in a court statement how he had made pressure-cooker bombs, grenades and suicide vests. He remained in prison for years before being released following the political upheaval in August 2024. Police now suspect he may have rebuilt a network and returned to explosives production.

Investigators have linked Mamun and Arif to several recent incidents, including an explosion at a madrasa in Keraniganj, blasts in Cumilla and Sayedabad, and the placement of a pipe bomb beneath an umbrella near Motijheel Metro Station during a Hindu religious procession.

Police said the pipe bomb was configured so that pressing a button on the umbrella could trigger an explosion. Its remote has not been recovered.

The emergence of remotely controlled devices has drawn particular attention as earlier militant groups in Bangladesh largely relied on timers and delay mechanisms. Authorities have also previously encountered explosives triggered by mobile phones.

Not every recent explosion, however, appears to be linked to the new technique. A weak blast outside a court in Barishal on Wednesday initially raised questions about remote detonation, but police said they found no wires, batteries or other components suggesting a conventional remotely controlled improvised explosive device.

The discoveries in Savar and Ashulia have nevertheless heightened concern among counterterrorism officials.
CTTC Additional Commissioner Mohammad Shamsul Haque said investigators were continuing to examine the incidents and the network behind them.

“We are still trying to arrest Mamun,” he said, adding that anyone found responsible would be brought to justice.

For investigators, the immediate challenge is to establish whether the recovered devices were isolated experiments or signs of a broader revival in militant bomb-making. With Mamun still at large, that question remains unanswered.