Veerpal Singh was shot dead by Saudab Singh, his sons Gyan Singh, Bhuwanesh and another man Surajpal over a land dispute in Kalupur area in Bisauli village in July 2007, prosecution sources said.
Veerpal's brother Kalicharan and nephew Arun were injured in the firing, they said.
After hearing the case, Judge M A Siddiqui held all the four accused guilty.
The court also imposed a fine of Rs 30,000 on each of the accused.