Indian national Mufti Obaidullah, a terrorist posing as a teacher since 1995, sent SMS messages in Persian, using English alphabets to his Pakistan-based Lashkar-e-Taiba (LeT) boss and spoke to him daily using six different cellphones, Bangladesh authorities say.
He knew "quite well", the chief of the Indian branch of the LeT, Ameer Reza, chief of Asif Reza Commando Force (ARCF). The force is named after the militant brother who was killed in Gujarat in 2001, Detective Branch (DB) officials told The Daily Star newspaper.
Obaidullah, remanded to judicial custody on Saturday, has been described by the Dhaka Metropolitan Police (DMP) that nabbed him as "one of the most wanted militants in India".
Deputy Commissioner Monirul Islam of DB (South) told The Daily Star: "The call lists of the mobile phones used by Obaidullah show that he made calls to Pakistan regularly and often to India."
"He talked to Ameer Reza every day over the phone. But we are yet to find out the subjects of their conversation," Monirul said.
DB sources said there is a strong possibility that LeT, ARCF, Harkatul Jihad al Islami Bangladesh (HUJI), and international mafia don Dawood Ibrahim's network are interconnected.
Obaidullah's immediate boss and LeT leader Mansur Ali alias Habibullah, another senior leader and Pakistani national Khurram Khoiyam, and two other leaders of the militant outfit are still holed up in Bangladesh, said sources.
They entered Bangladesh illegally at least three years before Obaidullah intruded into the country, added sources.
DB officials said they have been trying to track down the four most wanted LeT leaders in India. However, they suspect that Mansur Ali and Habibullah are two different persons.
All of them receive financial supports from India, DB sources said.
Monirul Hoq said: "He got Tk 7,000 ($100 approx) as monthly salary from the madrassa. It is quite impossible to meet the expenditure of a seven-member family and six mobile phones."
Quoting Obaidullah, DB officials said his organisation has a firm footing at Shibchar in Madaripur, Srinagar in Munshiganj and Nababganj in the capital with a good number of 'Jihadis' (militants) at the madrassas there.
LeT has been active in Bangladesh for the last 14 years, said intelligence sources quoting Obaidullah.
Obaidullah was caught following a tip off from another Indian militant, Abdur Rauf Daud Merchant, who fled the Indian law after being convicted for the murder of Bollywood music baron Gulshan Kumar in 1997.
Islamist militancy in Bangladesh got a spurt with the return in the 1990s of many veterans of the anti-Soviet war in Afghanistan.
The global scenario unfolding post-9/11 coincided with the coming to power of a government in Bangladesh that had the Jamaat-e-Islami sharing power with Khaleda Zia-led Bangladesh Nationalist Party (BNP).
The government denied the existence of militancy and the rise of leaders like Siddiqul Islam alias Bangla Bhai. It banned some of the militant bodies in 2005 following international criticism and threat of economic sanctions by the US Congress.