The 64-year-old leader died on Thursday night.
The Panchayat areas brought under the purview of the shutdown are Arikulam, Keezhariyoor, Chengottukavu and Chemanchery,
Police arrested the victim's neighbour Abhilash (33), who was also a former CPI(M) branch committee member of Peruvattur, and has been working as a temporary driver of Koyilandy Municipality.
The incident took place around 10 PM at Peruvattor Cheriyapuram Paradevatha temple premises, in between a cultural programme organised by the temple committee.
Police sources said Abhilash attacked Sathyanathan with a knife from the rear and he suffered injuries on the neck and back. Locals rushed the injured leader to a nearby taluk hospital, where doctors declared brought dead.
Later, the body was shifted to Kozhikode Medical College hospital for post-mortem.
Police claimed that after the incident, Abhilash surrendered and admitted his crime saying he had personal enmity with Sathyanathan.
The cremation will take place on Friday evening at Koyilandy. Before that the body will be kept at the town hall, Koyilandy, for people to pay their last respects to the departed leader, party sources said.
