Senior police officials who interrogated the four till Friday say the militants have patrons in the administration from top to bottom levels.
The militants used to get different types of support, especially in legal matters, in Rajshahi, Chapainawabganj and Naogaon where they already have a stronghold, the officials add.
"We are looking into the matter since the militants revealed the information," said Nazrul Islam, superintendent of police of Chapainawabganj.
The police are now looking for evidence which would substantiate the claims of the militants, the district police boss added.
The law enforcers handed over Selim alias Saifullah, military commander of the JMB offshoot, to the court on Friday on completion of five-day and three-day remand by Bholahat and Shibganj police in two cases.
Other militant leaders who were taken on remand and interrogated face-to-face with Selim are former JMB Rajshahi regional commander Abdur Rahim alias Shahadat, former JMB military commander Abdul Momin and Abdur Rakib alias Suman.
During the face-to-face interrogation held in Chapainawabganj, the four gave important information and said they have yet to fix single leadership as their new offshoot was formed in April.
They claim Selim alias Saifullah is the main organiser but they four altogether equally shared the leadership so far.
Abdur Rahim alias Shahadat was primarily considered for organisational activities, while Selim was looking after operational affairs.
However, a special intelligence team to combat militancy informed that Islam O Muslim has 10 commanders.
The militant leaders held three meetings to decide about the launch of the new offshoot. First they held a meeting in Raghunathpur in Nachole and then in Ranihati and Kansat in Shibganj, Chapainawabganj.
As the four sat in a meeting in Kansat for the last time in April, they decided to call the new organisation Islam O Muslim.
Selim brought in arms from India and they decided to use small weaponry for self-defence as the mainstream had threatened to kill them for "betrayal".
The militants claim they were on the JMB hit list as some of them betrayed the mainstream by misappropriating money. Selim took away around Tk 1.5 lakh from the JMB fund, they add.
The militant leaders had another aim of reorganising the inactive JMB leaders in the region and collecting small weaponry for their cadres. They collected some 16 small firearms and the police have recovered 14 of them.
Senior police officials term the arrest of the four a great relief as the law-enforcement agencies including the Rapid Action Battalion held them at very primary level.
The police last month arrested four militants in Chapainawabganj followed by the arrest of another three militants including Shahadat.
Later, Rab and BDR jointly arrested Selim in early this month.