Police said the victim, Aanandan, was on his motorcycle when CPI(M) activists, who were in a car, attacked him. He was rushed to a hospital where doctors pronounced him dead. The incident occurred around 1 pm in Nenmanikkara.
Anandan, who was 23, hailed from Brahmakulam. He was an accused in a case relating to the murder of a CPI(M) worker in 2013.
He was currently out on bail.
Reacting to the incident, BJP state president Kummanam Rajasekharan said, "Leftist terror bloodshed continues in Kerala. BJP Karyakartha Anand murdered brutally in Guruvayur, Thrissur. Communist terror surging in the state with jungle raj in Kerala to aid."
Kerala has been witnessing frequent political clashes with the CPI(M) and the RSS-BJP are engaged in a violent turf war in the state. Both the parties have been accusing eachother of 'political killings'.
BJP has alleged that as many as 120 BJP workers, 84 in Kannur alone, have been killed in Kerala since 2001. It has claimed that 14 of these killings have taken place since Chief Minister Pinarayi Vijayan took over the reins of the government last year.
The CPI(M) has in turn, accused BJP and RSS of resorting to violence and denied the involvement of its government and leadership in political killings.
(With PTI inputs)