Three people have been arrested in the murder of a former village head in Uttar Pradesh's Amethi, who worked closely with BJP leader Smriti Irani during her Lok Sabha campaign, the police said on Monday, adding that it was a case of "local-level political rivalry".

"We have arrested three murder suspects. Two suspects are still absconding and we will catch them soon. On the basis of all evidence it is very clear that the five murder suspects and the victim had local-level political rivalry," Uttar Pradesh police chief OP Singh said.

Surendra Singh, a BJP worker, was attacked at his home at around 3 am on Sunday; he died later at a hospital in Lucknow where he was taken for treatment, the police said.

Smriti Irani attended the funeral later in the day and said she will "move the Supreme Court, if needed, to seek death sentence" for the killers.

Ms Irani had virtually stationed herself in Amethi ahead of the elections. Surendra Singh had actively participated in her election campaign and had earned praise from the BJP leader in her speeches at public meetings.

Smriti Irani defeated Rahul Gandhi by over 55,000 votes in the constituency that he had been winning since 2004. The loss of Amethi had pushed the Congress's tally in Uttar Pradesh - a state it once dominated in - to a single seat.