A local CPI-M leader and chairman of Punalur Municipality, M A Rajagopal, and another party worker were sentenced to life imprisonment by a local court in Kollam on Wednesday.
The case against the CPI-M activists was that they hurled bombs and killed RSS worker Rajesh at Punalur in 2002, before Rajagopal became the municipal chairman.
Second class Judicial Magistrated, K K Gopalakirshnan, found Rajagopal and Santhosh alias Mariappan guilty of charges including murder, conspiracy and illegal possession of arms.
Five other accused in the case including distric secretary of CPI-M's youth wing S Biju were acquitted in the case.
The case against the guilty was that they threw a country made bomb at Rajesh wile he was sitting on the half-wall of a culvert on the road near Punalur town on June 9, 2002.