Additional Sessions Judge Anupati Ram Yadav found Munna, Jugnu and Markandey guilty of killing Vikram Yadav in Islamabad village on August 7, 2000 and awarded them the punishment yesterday.
Yadav was shot dead by the trio when he was returning home after attending a court case, the prosecution sources said.
The court also imposed a fine of Rs 5,000 on each of the convicts.