A mobile court sentenced four people to 20 days' imprisonment each for lifting stones from the Teesta river illegally at Dowani village in Hatibandha upazila of the district on Wednesday night.
The convicts are Hanif Islam, son of Abdul Haque, Golam Robbani, son of Abul Hossain, Mojibur Rahman, son of Zahir Uddin and Mahatab Uddin, son of Abdul Jabbar of Chhotokhata village in Nilphamari's Dimla upazila.
Hatibandha Upazila Nirbahi Officer Samiul Amin, also the executive magistrate, led the court, said Omar Farooque, officer-in-charge of Hatibandha Police Station.
On information, a police team raided the area and arrested the four while they were lifting stones from the river using dredging machine, said the OC.
The arrestees were later produced before the court that found them guilty and pronounced the verdict, said the police official, adding that they were sent to jail yesterday morning.