Two CPI (M) workers have been taken into custody for the brutal murder of a Youth Congress worker near Kannur around a week ago, police said on Sunday.
Accused Akash and Rijin Raj are also allegedly involved in another murder.
However, the opposition Congress said the two accused were not the real culprits while the Bharatiya Janata Party demanded a CBI probe.
Congress worker Shuhaib, 30, was waiting at an eatery near Mattanoor around 10.45 p.m on Monday when four persons riding a car hurled bombs to create panic and then fatally slashed him with a sword.
A picture of both allegedly posing along Chief Minister Pinarayi Vijayan and Communist Party of India-Marxist State Secretary Kodiyeri Balakrishnan has now come out.
"To the best of our knowledge, the two CPI-M workers in custody are not the real culprits. What is even more intriguing is that police did not arrest them. Instead, local CPI-M leaders presented the two accused at the police station. All this while the CPI-M leadership was saying that the party had no role in the murder but it has now been proved wrong," senior Congress leader K Sudhakaran said.
Kodiyeri Balakrishnan, however, downplayed the issue and said the ruling party will take action if any party member was involved.
"Let police do their job and decide who are the culprits," said Balakrishnan.
State BJP President Kummanem Rajasekheran told the media that the two accused were housed at the state CPI (M) headquarters in Kannur.
"For long, state CPI (M) first denies role in such murders but later it comes to light that the accused are CPI (M) workers. What is suspicious now is that the two were presented to police by local CPI (M) leaders. For the truth to come out, only a CBI probe will suffice," said Rajasekheran.