Assam Police seized 12 Bangladeshi nationals in Goalpara town on the night of October 9 after a bus from Guwahati halted near the bus stand.
The group, comprising six adults, three children and a newborn, includes Sirajul Islam, his wife Jobeda Begum, their kids, Amir Ali and others.
They say a broker named Sabuj lured them with quarry work promises. The men crossed the border via a forest on October 6.
They remained overnight at Goalpara Sadar Police Station. On October 10, they were moved to the Reserve Police Line at Beltala for interrogation.
After questioning, they were transferred to the Matia Transit Camp. Legal and repatriation procedures are expected to follow.