A Trinamool Congress activist was killed at Raikash village in Nadia district on Friday, police said.
The blood-soaked body of Surajit Sarkar (45), an active local member of the party, was found by his family member a little distance away from his home.
Police arrested four persons in connection with the murder but their political identity was not revealed.
Family members said Surajit came out from his residence at around 4 am for irrigating his field and found in a bleeding state by others later.
He was rushed to Haringhata rural hospital at around 6 am and was declared brought dead.
While his son Mithun Sarkar claimed the deceased had named some of the culprits, all known to be CPI(M) members in the area, before death, CPI(M) sources said the murder was a fallout of feud within the family.
The son later lodged a complaint with Haringhata police station against 11 persons.
Chanchal Debnath, Trinamool member of Nadia Zilla Parishad said CPI(M) men lynched Surajit with crowbar, shovel.