Some persons set fire to the houses of upper caste Thakurs in Shabbirpur village ahead of the arrival of BSP chief Mayawati there, police sources said.
District officials rushed to the scene and pacified members of the Thakur community.
Later, some unidentified, sword wielding persons attacked a Bolero car of BSP supporters, who had come from Sarsawa.
The sources said the attackers fired their guns and wielded batons, killing Ashish (24) on the spot and injuring four others.
The injured have been admitted to the district hospital.
On May 5, a Dalit group had objected to a procession of Thakurs in Shabbirpur to mark the birth anniversary of Rajput king Maharana Pratap, triggering violence, in which one person was killed and over 15 were injured.
Dalit victims of the clashes say upper caste Thakurs had earlier prevented them from installing a statue of BR Ambedkar on the premises of the Ravidas temple in the village.