Over 10,000 cattle and other items worth Rs 40 crore were seized along the border in the last one year, the BSF IG said.
The BSF suspects the criminals used the passage through the culvert for carrying out smuggling and other crimes.
This is for the first time in four decades that the biannual conference is being held outside Delhi.
Enamul Haque was earlier arrested in March 2018 by the CBI for allegedly bribing a BSF Commandant, Jibu T Mathew, who was held at the Alappuzha railway station in January 2018 with Rs 47 lakh cash.
Five Bangladeshis and 12 Indian nationals, including one tout, were apprehended by the border guards while illegally crossing over to this side near Ramnagar outpost in Nadia district.
All four were nabbed on October 7 as they were attempting to cross the Ichhamati River, which separates India and Bangladesh, the BSF spokesperson said.
The central agency claimed to have come across leads showing the involvement of a section of customs officers posted in the districts.
As per an agreement between India and Myanmar, the locals on either side can move up to 16 km within each other’s territory without documents and stay there for a while.