Ariful had accompanied his grandparents Hashimuddin Sheikh and Mafroza Khatun to the neighbouring country in April last year to visit an ailing relative.
They were arrested while returning from Bangladesh on April 15, 2011 after they were found travelling without proper travel documents, police said. They were sentenced to a two-month jail term and fined Taka 500.
Although their jail term ended in June last, they were behind bars for almost a year.
The three persons were today returning to India by the Gede border checkpoint in Nadia district, the police said.