Additional district and sessions judge J K Sinha passed the order convicting Rajesh Kumar Mahto and Bajrangi Mahto.
The court also imposed a fine of Rs 10,000 on each of the two.
According to prosecution, the two had fatally attacked Kishore Rai with a sharp object at Lakrikola village under Banka police station on November 25, 1996 following an enmity between them.
The two had buried the body which was recovered four days later by the police.
The victim's father had lodged a named FIR against the two persons charging them with the murder of his son.