The Bangladeshi was arrested late on Sunday night near the Allahabad railway junction where he was roaming in a "suspicious manner", the police said adding that he was taken to Shahganj police station for interrogation.
Preliminary investigation by senior officials, including superintendent of Police (city) A K Vijeta, revealed that Naseem was a resident of Dhaka and had sneaked into the country a few weeks ago without a visa and other valid documents.
On the basis of the interrogation, the police have conducted raids in various parts of the old city area and also sought call details of various telephone booths situated in the vicinity of the railway station and bus terminus.