
Narayanganj Senior District and Sessions Judge Abu Shamim Azad handed down the verdict, said Court Police Inspector Abdus Samad.
The lifers are--Sajal Barman, son of Narayan Barman; Sanjir Barman, son of Pagal Chan Barman of Araihazar upazila; Ruma, daughter of Aynal Haque; and Rumi, daughter of Kader of the Fatullah area. All of them were tried in absentia.
The court also fined Tk 50,000 each, in default, to suffer two years of rigorous imprisonment.
According to the prosecution, Bhajan Chandra Das, 23, son of Phony Chandra Das of Madhabdi upazila in Narsingdi district, was abducted by the convicts on April 13, 2017.
They later demanded Tk 20,000 as ransom from his family for his release.
The convicts later killed Bhajan Chandra and buried his body on April 16, 2017.
A case was filed with Araihazar Police Station in connection with the incident.
Following the investigation, police identified the accused and submitted a charge sheet against them, reports UNB.