Ravi Maurya was shot dead near Devkhari Bazar while he was returning home after attending a meeting at SP MLA Baijnath Paswan's residence, they said.
His associate Sanjit was seriously injured in the firing and has been referred to Varanasi, police said, adding efforts are on to nab the absconding accused.
Meanwhile, enraged over the incident local residents blocked Ghazipur-Azamgarh road and damaged panels of several buses.