The BJP's Ballia Sadar candidate Dayashankar Singh has been allegedly attacked in Akhar village after which a case was lodged against Samajwadi Party nominee Narad Rai and his supporters, police said on Thursday.
Narad Rai's nephew Ashish Rai has been arrested, they said.
SHO of Dubhar police station said that on the complaint of Dayashankar Singh, a case was registered on Wednesday night against Rai and his supporters on charges of threatening to kill and damage a vehicle.
In the complaint, Dayashankar Singh claimed that he was returning home around 11.30 pm when supporters of Samajwadi Party candidate and former minister Narad Rai attacked him.
He alleged that it was a big conspiracy to kill him.
Singh also told the police officials who reached the spot after the incident that Rai's supporters had fled leaving a vehicle that belongs to the Mukhtar Ansari gang.
It was also alleged that the vehicle of Tunji Pathak, a former BSP MP who recently joined the BJP, was damaged in the incident but no one was injured.
Police said a probe into the incident was underway.