The accused Mohibul Islam, 25, is a resident of Uttar Atrai village in Palashbari union, Parbatipur upazila, and a student at a private university in Dhaka.
Tipped-off, the Dhaka Metropolitan Detective Police (DMP DB) launched a shadow investigation into the alleged leak of the BCS exam paper scheduled for Friday.
Upon learning of the probe, Mohibul reportedly left Dhaka and attempted to return home to Parbatipur by boarding the Panchagarh-bound intercity Ekota Express on Thursday morning (18 September).
Using information technology, investigators tracked his journey and coordinated with railway police to identify him onboard.
A team from the Dinajpur District Detective Branch (DB) then boarded the train at Birampur Railway Station and detained him near Parbatipur Station on Thursday evening, reports UNB.
Rafiquzzaman, officer-in-charge (OC) of Dinajpur DB, said that the suspect was handed over to the DMP Detective Branch later that night for further investigation.