Counterterrorism officials yesterday claimed to have arrested an upazila unit “Neo JMB” commander who leads a syndicate that supplied ingredients for grenades and arms used in the Gulshan attack from the Indian border area near Chapainawabganj.

A team of Counter Terrorism and Transnational Crime (CTTC) unit of the Dhaka Metropolitan Police arrested Mizanur Rahman alias Boro Mizan, 60, in-charge of bordering Shibganj upazila unit of “Neo JMB” in a bus near Kakoli crossing in the capital around 10:00pm on Tuesday.

“We intercepted a bus following information that Boro Mizan was coming to Dhaka and arrested him,” said CTTC Assistant Commissioner Ahmedul Islam who led the raid.

He added the syndicate headed by Boro Mizan and Chhoto Mizan alias Tara, another “Neo JMB” leader of the region, was the only gang that smuggled in grenade-making materials like detonators and power gel for the outfit.

Apart from Gulshan attack, the gang ensured ingredients for improvised grenades that were used in all attacks perpetrated by “Neo JMB” in recent years, counterterrorism officials said.

The syndicate also used to supply small firearms along with some other smuggling gangs, they added.

AC Ahmedul said Boro Mizan was the military commander of another militant group “Jund At-Tawheed Wal Khilafah”. Later, he joined “Neo JMB” after meeting with its chief coordinator Tamim Chowdhury, who asked Mizan to supply arms and ammunition to the outfit.

Investigators first learned about activities of “Jund At-Tawheed Wal Khilafah” on May 31, 2015 following arrest of Abdullah Al-Galib, 27, in the capital's Baridhara area. Son of an ex-army official, Galib reportedly launched activities of the outfit in Bangladesh.

At that time, detectives also claimed the outfit used to follow the strategy of Islamic State.

Asked how many members of the syndicate were still on the run, AC Ahmedul said they were still hunting Chhoto Mizan alias Tara and three to four other members of the syndicate.

On November 2 last year, the CTTC unit arrested four suspected “Neo JMB” operatives, also members of the syndicate, in the capital's Darus Salam area. They were Abu Taher, Mizanur Rahman, Selim Mia and Toufiqul Islam alias Doctor Toufiq.

Police then claimed the arrestees had admitted that Chhoto Mizan delivered raw materials and firearms, including pistols, to Tamim Ahmed Chowdhury and Nurul Islam Marzan, the key planners of the July 1 attack on the Gulshan eatery.

Tara had collected the arms and explosive-making materials from Chapainawabganj border through the four, they added.

Officials say the arms and other materials came to Dhaka in baskets of mangoes and other seasonal fruits.

Police also seized a 9mm pistol and 787 detonators, the main ingredient of handmade grenades, from the possession of the four.

On the night of July 1, militants seized the Gulshan café and killed 20 hostages, including nine Italian, seven Japanese and one Indian citizen.

The over-12-hour siege ended after the launch of a commando operation in which five terrorists and a café chef were killed.

The authorities maintain that “Neo JMB”, an offshoot of the banned militant outfit Jama'atul Mujahideen Bangladesh (JMB), carried out the attack.