Chandrasekharan (50) was attacked and killed by unidentified assailants at Vallikkad near Vatakara in Kozhikode district.
The assailants who came by car attacked him while he was riding a motorcycle alone. Country-made bombs were hurled at him and when he fell off the motorcycle, he was hacked to death with sharp weapons.
Chandrasekharan began his political career as an activist of CPI(M)'s campus wing SFI. He later became a whole-timer of the party in its stronghold.
He was once known as a supporter of senior leader V S Achuthanandan and was said to have incurred the wrath of the faction loyal to the party state Secretary Pinarayi Vijayan.
Kerala Chief Minister Oommen Chandy and Home Minister Thiruvanchur Radhakrishnan were among those who condemned the murder. Chandy is expected to arrive at Kozhikode later today.
Union Minister of State for Home Mullapally Ramachandran and socialist Janata Democratic leader M P Veerendra Kumar have also condemned the murder.