Bangladeshi national Mohammad Mafizur Rahaman, who was detained in Agartala earlier this week, has links with Bangladesh-based terror group Harkat-ul-Jehad-i-Islami (HuJI) and was involved in criminal activities in Bangladesh before he was recruited by the ISI, sources said.

“We had Rahaman under observation in Agartala for nearly two months. He presented himself as a businessman and had a lavish lifestyle. Although the defence-related documents recovered from him are not highly classified, they contained specific information related to the deployment and infrastructure of the Assam Rifles and other central security forces deployed in Tripura,” a source said.

State-based investigating agencies have expressed surprise at the extent of penetration of the security forces apparatus in West Bengal.

Rahaman, alias Suman Majumdar, alias Mamun Mian, was brought to Kolkata on Saturday and produced in a Howrah courtroom on Sunday. He was arrested by the CID branch of Kolkata police as part of a joint operation with security forces.

The initial tip-off regarding Rahaman had come following the arrest of two alleged activists of the HuJI— Mohammad Shamim Akhtar and Abdul Malik, alias Alamgir— from Shalimar in Howrah district on January 16 by the CID.

During interrogation, both had confessed to recruiting a BSF head constable now posted in North Bengal, and an officer of the Indian Navy named K S Singh. Rahaman is said to have entered India illegally through the international border with Nadia district.

Rajeev Kumar, Special IGP (Special Operations Group) confirmed that the accused had a criminal past in Bangladesh.