Sonu had been missing for a week and his body was recovered last evening from a pond. His throat had been slit.
SP (Crime) Pradeep Gupta said a case was registered against Ashok, his brother Sudhir, uncle Sushil and cousin Ravi and they have been arrested.
They were injured in the attack by the family members of Sonu and were shifted to a hospital.
(Reopens MDS1)
More From This Section
had died before reaching the hospital, party State President, Kummanam Rajasekharan, said.
In 2002, the deceased youth's father Uttaman, was killed allegedly by the CPI(M), he said.
A tense situation is prevailing in the area following the incident.
Meanwhile, protesting against the murder of their worker, BJP today called for a dawn-to-dusk state-wide hartal tomorrow.